16 files changed, 1344 insertions, 2 deletions
diff --git a/src/assistant/help/help.pro b/src/assistant/help/help.pro
index cd7781dde..ff7a81374 100644
--- a/src/assistant/help/help.pro
+++ b/src/assistant/help/help.pro
@@ -12,10 +12,13 @@ DEFINES -= QT_ASCII_CAST_WARNINGS
 RESOURCES += helpsystem.qrc
 SOURCES += \
     qcompressedhelpinfo.cpp \
+    qfilternamedialog.cpp \
     qhelpenginecore.cpp \
     qhelpengine.cpp \
     qhelpfilterdata.cpp \
     qhelpfilterengine.cpp \
+    qhelpfiltersettings.cpp \
+    qhelpfiltersettingswidget.cpp \
     qhelpdbreader.cpp \
     qhelpcontentwidget.cpp \
     qhelpindexwidget.cpp \
@@ -26,15 +29,19 @@ SOURCES += \
     qhelpsearchindexwriter_default.cpp \
     qhelpsearchindexreader_default.cpp \
     qhelpsearchindexreader.cpp \
-    qhelp_global.cpp
+    qhelp_global.cpp \
+    qoptionswidget.cpp
 
 HEADERS += \
     qcompressedhelpinfo.h \
+    qfilternamedialog_p.h \
     qhelpenginecore.h \
     qhelpengine.h \
     qhelpengine_p.h \
     qhelpfilterdata.h \
     qhelpfilterengine.h \
+    qhelpfiltersettings_p.h \
+    qhelpfiltersettingswidget.h \
     qhelp_global.h \
     qhelpdbreader_p.h \
     qhelpcontentwidget.h \
@@ -45,6 +52,12 @@ HEADERS += \
     qhelpsearchresultwidget.h \
     qhelpsearchindexwriter_default_p.h \
     qhelpsearchindexreader_default_p.h \
-    qhelpsearchindexreader_p.h
+    qhelpsearchindexreader_p.h \
+    qoptionswidget_p.h
+
+FORMS += \
+    qhelpfiltersettingswidget.ui \
+    qfilternamedialog.ui
+
 
 load(qt_module)
diff --git a/src/assistant/help/helpsystem.qrc b/src/assistant/help/helpsystem.qrc
index 785923aad..611008639 100644
--- a/src/assistant/help/helpsystem.qrc
+++ b/src/assistant/help/helpsystem.qrc
@@ -4,5 +4,9 @@
         <file>images/1rightarrow.png</file>
         <file>images/3leftarrow.png</file>
         <file>images/3rightarrow.png</file>
+        <file>images/mac/minus.png</file>
+        <file>images/mac/plus.png</file>
+        <file>images/win/minus.png</file>
+        <file>images/win/plus.png</file>
     </qresource>
 </RCC>
diff --git a/src/assistant/help/images/mac/minus.png b/src/assistant/help/images/mac/minus.png
new file mode 100644
index 000000000..8d2eaed52
--- /dev/null
+++ b/src/assistant/help/images/mac/minus.png
diff --git a/src/assistant/help/images/mac/plus.png b/src/assistant/help/images/mac/plus.png
new file mode 100644
index 000000000..1ee45423e
--- /dev/null
+++ b/src/assistant/help/images/mac/plus.png
diff --git a/src/assistant/help/images/win/minus.png b/src/assistant/help/images/win/minus.png
new file mode 100644
index 000000000..c0dc274bb
--- /dev/null
+++ b/src/assistant/help/images/win/minus.png
diff --git a/src/assistant/help/images/win/plus.png b/src/assistant/help/images/win/plus.png
new file mode 100644
index 000000000..ecf058941
--- /dev/null
+++ b/src/assistant/help/images/win/plus.png
diff --git a/src/assistant/help/qfilternamedialog.cpp b/src/assistant/help/qfilternamedialog.cpp
new file mode 100644
index 000000000..8563a3355
--- /dev/null
+++ b/src/assistant/help/qfilternamedialog.cpp
@@ -0,0 +1,65 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtWidgets/QPushButton>
+
+#include "qfilternamedialog_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QFilterNameDialog::QFilterNameDialog(QWidget *parent)
+    : QDialog(parent)
+{
+    m_ui.setupUi(this);
+    connect(m_ui.buttonBox->button(QDialogButtonBox::Ok), &QAbstractButton::clicked,
+            this, &QDialog::accept);
+    connect(m_ui.buttonBox->button(QDialogButtonBox::Cancel), &QAbstractButton::clicked,
+            this, &QDialog::reject);
+    connect(m_ui.lineEdit, &QLineEdit::textChanged,
+            this, &QFilterNameDialog::updateOkButton);
+    m_ui.buttonBox->button(QDialogButtonBox::Ok)->setDisabled(true);
+}
+
+void QFilterNameDialog::setFilterName(const QString &filter)
+{
+    m_ui.lineEdit->setText(filter);
+    m_ui.lineEdit->selectAll();
+}
+
+QString QFilterNameDialog::filterName() const
+{
+    return m_ui.lineEdit->text();
+}
+
+void QFilterNameDialog::updateOkButton()
+{
+    m_ui.buttonBox->button(QDialogButtonBox::Ok)
+        ->setDisabled(m_ui.lineEdit->text().isEmpty());
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qfilternamedialog.ui b/src/assistant/help/qfilternamedialog.ui
new file mode 100644
index 000000000..1da584a80
--- /dev/null
+++ b/src/assistant/help/qfilternamedialog.ui
@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>FilterNameDialogClass</class>
+ <widget class="QDialog" name="FilterNameDialogClass">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>312</width>
+    <height>77</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Add Filter</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Filter Name:</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="1">
+    <widget class="QLineEdit" name="lineEdit"/>
+   </item>
+   <item row="1" column="0">
+    <spacer name="verticalSpacer">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="sizeHint" stdset="0">
+      <size>
+       <width>20</width>
+       <height>1</height>
+      </size>
+     </property>
+    </spacer>
+   </item>
+   <item row="2" column="0" colspan="2">
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <layoutdefault spacing="6" margin="11"/>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/src/assistant/help/qfilternamedialog_p.h b/src/assistant/help/qfilternamedialog_p.h
new file mode 100644
index 000000000..f805e9308
--- /dev/null
+++ b/src/assistant/help/qfilternamedialog_p.h
@@ -0,0 +1,56 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QFILTERNAMEDIALOG_H
+#define QFILTERNAMEDIALOG_H
+
+#include <QtWidgets/QDialog>
+#include "ui_qfilternamedialog.h"
+
+QT_BEGIN_NAMESPACE
+
+class QFilterNameDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    QFilterNameDialog(QWidget *parent = nullptr);
+
+    void setFilterName(const QString &filter);
+    QString filterName() const;
+
+private slots:
+    void updateOkButton();
+
+private:
+    Ui::FilterNameDialogClass m_ui;
+};
+
+QT_END_NAMESPACE
+
+#endif // QFILTERNAMEDIALOG_H
diff --git a/src/assistant/help/qhelpfiltersettings.cpp b/src/assistant/help/qhelpfiltersettings.cpp
new file mode 100644
index 000000000..e9a1c3f4e
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettings.cpp
@@ -0,0 +1,170 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qhelpfiltersettings_p.h"
+#include "qhelpfilterdata.h"
+
+#include <QtCore/QMap>
+#include <QtHelp/QHelpFilterEngine>
+
+QT_BEGIN_NAMESPACE
+
+class QHelpFilterSettingsPrivate : public QSharedData
+{
+public:
+    QHelpFilterSettingsPrivate() = default;
+    QHelpFilterSettingsPrivate(const QHelpFilterSettingsPrivate &other) = default;
+    ~QHelpFilterSettingsPrivate() = default;
+
+    QMap<QString, QHelpFilterData> m_filterToData;
+    QString m_currentFilter;
+};
+
+QHelpFilterSettings::QHelpFilterSettings()
+    : d(new QHelpFilterSettingsPrivate)
+{
+}
+
+QHelpFilterSettings::QHelpFilterSettings(const QHelpFilterSettings &) = default;
+
+QHelpFilterSettings::QHelpFilterSettings(QHelpFilterSettings &&) = default;
+
+QHelpFilterSettings::~QHelpFilterSettings() = default;
+
+QHelpFilterSettings &QHelpFilterSettings::operator=(const QHelpFilterSettings &) = default;
+
+QHelpFilterSettings &QHelpFilterSettings::operator=(QHelpFilterSettings &&) = default;
+
+void QHelpFilterSettings::setFilter(const QString &filterName,
+                                    const QHelpFilterData &filterData)
+{
+    d->m_filterToData.insert(filterName, filterData);
+}
+
+void QHelpFilterSettings::removeFilter(const QString &filterName)
+{
+    d->m_filterToData.remove(filterName);
+}
+
+QStringList QHelpFilterSettings::filterNames() const
+{
+    return d->m_filterToData.keys();
+}
+
+QHelpFilterData QHelpFilterSettings::filterData(const QString &filterName) const
+{
+    return d->m_filterToData.value(filterName);
+}
+
+QMap<QString, QHelpFilterData> QHelpFilterSettings::filters() const
+{
+    return d->m_filterToData;
+}
+
+void QHelpFilterSettings::setCurrentFilter(const QString &filterName)
+{
+    d->m_currentFilter = filterName;
+}
+
+QString QHelpFilterSettings::currentFilter() const
+{
+    return d->m_currentFilter;
+}
+
+QHelpFilterSettings QHelpFilterSettings::readSettings(QHelpFilterEngine *filterEngine)
+{
+    QHelpFilterSettings filterSettings;
+
+    const QStringList allFilters = filterEngine->filters();
+    for (const QString &filter : allFilters)
+        filterSettings.setFilter(filter, filterEngine->filterData(filter));
+
+    filterSettings.setCurrentFilter(filterEngine->activeFilter());
+
+    return filterSettings;
+}
+
+static QMap<QString, QHelpFilterData> subtract(const QMap<QString, QHelpFilterData> &minuend,
+                                               const QMap<QString, QHelpFilterData> &subtrahend)
+{
+    QMap<QString, QHelpFilterData> result = minuend;
+
+    for (auto itSubtrahend = subtrahend.cbegin(); itSubtrahend != subtrahend.cend(); ++itSubtrahend) {
+        auto itResult = result.find(itSubtrahend.key());
+        if (itResult != result.end() && itSubtrahend.value() == itResult.value())
+            result.erase(itResult);
+    }
+
+    return result;
+}
+
+bool QHelpFilterSettings::applySettings(QHelpFilterEngine *filterEngine,
+                                        const QHelpFilterSettings &settings)
+{
+    bool changed = false;
+    const QHelpFilterSettings oldSettings = readSettings(filterEngine);
+
+    const QMap<QString, QHelpFilterData> filtersToRemove = subtract(
+                oldSettings.filters(),
+                settings.filters());
+    const QMap<QString, QHelpFilterData> filtersToAdd = subtract(
+                settings.filters(),
+                oldSettings.filters());
+
+    const QString &currentFilter = filterEngine->activeFilter();
+
+    for (const QString &filter : filtersToRemove.keys()) {
+        filterEngine->removeFilter(filter);
+        if (currentFilter == filter && !filtersToAdd.contains(filter))
+            filterEngine->setActiveFilter(QString());
+        changed = true;
+    }
+
+    for (auto it = filtersToAdd.cbegin(); it != filtersToAdd.cend(); ++it) {
+        filterEngine->setFilterData(it.key(), it.value());
+        changed = true;
+    }
+
+    if (changed)
+        filterEngine->setActiveFilter(settings.currentFilter());
+
+    return changed;
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpfiltersettings_p.h b/src/assistant/help/qhelpfiltersettings_p.h
new file mode 100644
index 000000000..50e30e492
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettings_p.h
@@ -0,0 +1,85 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QHELPFILTERSETTINGS_H
+#define QHELPFILTERSETTINGS_H
+
+#include <QtCore/QSharedDataPointer>
+
+QT_BEGIN_NAMESPACE
+
+template <class K, class T>
+class QMap;
+class QHelpFilterData;
+class QHelpFilterEngine;
+class QHelpFilterSettingsPrivate;
+
+class QHelpFilterSettings final
+{
+public:
+    QHelpFilterSettings();
+    QHelpFilterSettings(const QHelpFilterSettings &other);
+    QHelpFilterSettings(QHelpFilterSettings &&other);
+    ~QHelpFilterSettings();
+
+    QHelpFilterSettings &operator=(const QHelpFilterSettings &other);
+    QHelpFilterSettings &operator=(QHelpFilterSettings &&other);
+
+    void swap(QHelpFilterSettings &other) noexcept
+    { d.swap(other.d); }
+
+    void setFilter(const QString &filterName, const QHelpFilterData &filterData);
+    void removeFilter(const QString &filterName);
+    QStringList filterNames() const;
+    QHelpFilterData filterData(const QString &filterName) const;
+    QMap<QString, QHelpFilterData> filters() const;
+
+    void setCurrentFilter(const QString &filterName);
+    QString currentFilter() const;
+
+    static QHelpFilterSettings readSettings(QHelpFilterEngine *filterEngine);
+    static bool applySettings(QHelpFilterEngine *filterEngine, const QHelpFilterSettings &settings);
+
+private:
+    QSharedDataPointer<QHelpFilterSettingsPrivate> d;
+};
+
+QT_END_NAMESPACE
+
+#endif // QHELPFILTERSETTINGS_H
diff --git a/src/assistant/help/qhelpfiltersettingswidget.cpp b/src/assistant/help/qhelpfiltersettingswidget.cpp
new file mode 100644
index 000000000..15cc4f475
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettingswidget.cpp
@@ -0,0 +1,428 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qhelpfilterdata.h"
+#include "qhelpfiltersettings_p.h"
+#include "qhelpfiltersettingswidget.h"
+#include "ui_qhelpfiltersettingswidget.h"
+#include "qfilternamedialog_p.h"
+
+#include <QtWidgets/QMessageBox>
+#include <QtCore/QVersionNumber>
+
+QT_BEGIN_NAMESPACE
+
+static QStringList versionsToStringList(const QList<QVersionNumber> &versions)
+{
+    QStringList versionList;
+    for (const QVersionNumber &version : versions)
+        versionList.append(version.isNull() ? QString() : version.toString());
+    return versionList;
+}
+
+static QList<QVersionNumber> stringListToVersions(const QStringList &versionList)
+{
+    QList<QVersionNumber> versions;
+    for (const QString &versionString : versionList)
+        versions.append(QVersionNumber::fromString(versionString));
+    return versions;
+}
+
+class QHelpFilterSettingsWidgetPrivate
+{
+    QHelpFilterSettingsWidget *q_ptr;
+    Q_DECLARE_PUBLIC(QHelpFilterSettingsWidget)
+public:
+    QHelpFilterSettingsWidgetPrivate() = default;
+
+    QHelpFilterSettings filterSettings() const;
+    void setFilterSettings(const QHelpFilterSettings &settings);
+
+    void updateCurrentFilter();
+    void componentsChanged(const QStringList &components);
+    void versionsChanged(const QStringList &versions);
+    void addFilterClicked();
+    void renameFilterClicked();
+    void removeFilterClicked();
+    void addFilter(const QString &filterName,
+                   const QHelpFilterData &filterData = QHelpFilterData());
+    void removeFilter(const QString &filterName);
+    QString getUniqueFilterName(const QString &windowTitle,
+                                const QString &initialFilterName);
+    QString suggestedNewFilterName(const QString &initialFilterName) const;
+
+    QMap<QString, QListWidgetItem *> m_filterToItem;
+    QHash<QListWidgetItem *, QString> m_itemToFilter;
+
+    Ui::QHelpFilterSettingsWidget m_ui;
+    QStringList m_components;
+    QList<QVersionNumber> m_versions;
+    QHelpFilterSettings m_filterSettings;
+};
+
+void QHelpFilterSettingsWidgetPrivate::setFilterSettings(const QHelpFilterSettings &settings)
+{
+    QString currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty()) {
+        if (!m_filterSettings.currentFilter().isEmpty())
+            currentFilter = m_filterSettings.currentFilter();
+        else
+            currentFilter = settings.currentFilter();
+    }
+
+    m_filterSettings = settings;
+
+    m_ui.filterWidget->clear();
+    m_ui.componentWidget->clear();
+    m_ui.versionWidget->clear();
+    m_itemToFilter.clear();
+    m_filterToItem.clear();
+
+    for (const QString &filterName : m_filterSettings.filterNames()) {
+        QListWidgetItem *item = new QListWidgetItem(filterName);
+        m_ui.filterWidget->addItem(item);
+        m_itemToFilter.insert(item, filterName);
+        m_filterToItem.insert(filterName, item);
+        if (filterName == currentFilter)
+            m_ui.filterWidget->setCurrentItem(item);
+    }
+
+    if (!m_ui.filterWidget->currentItem() && !m_filterToItem.isEmpty())
+        m_ui.filterWidget->setCurrentItem(m_filterToItem.first());
+
+    updateCurrentFilter();
+}
+
+QHelpFilterSettings QHelpFilterSettingsWidgetPrivate::filterSettings() const
+{
+    return m_filterSettings;
+}
+
+void QHelpFilterSettingsWidgetPrivate::updateCurrentFilter()
+{
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+
+    const bool filterSelected = !currentFilter.isEmpty();
+    m_ui.componentWidget->setEnabled(filterSelected);
+    m_ui.versionWidget->setEnabled(filterSelected);
+    m_ui.renameButton->setEnabled(filterSelected);
+    m_ui.removeButton->setEnabled(filterSelected);
+
+    m_ui.componentWidget->setOptions(m_components,
+            m_filterSettings.filterData(currentFilter).components());
+    m_ui.versionWidget->setOptions(versionsToStringList(m_versions),
+            versionsToStringList(m_filterSettings.filterData(currentFilter).versions()));
+}
+
+void QHelpFilterSettingsWidgetPrivate::componentsChanged(const QStringList &components)
+{
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    QHelpFilterData filterData = m_filterSettings.filterData(currentFilter);
+    filterData.setComponents(components);
+    m_filterSettings.setFilter(currentFilter, filterData);
+}
+
+void QHelpFilterSettingsWidgetPrivate::versionsChanged(const QStringList &versions)
+{
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    QHelpFilterData filterData = m_filterSettings.filterData(currentFilter);
+    filterData.setVersions(stringListToVersions(versions));
+    m_filterSettings.setFilter(currentFilter, filterData);
+}
+
+void QHelpFilterSettingsWidgetPrivate::addFilterClicked()
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    const QString newFilterName = getUniqueFilterName(q->tr("Add Filter"),
+                                  suggestedNewFilterName(q->tr("New Filter")));
+    if (newFilterName.isEmpty())
+        return;
+
+    addFilter(newFilterName);
+}
+
+void QHelpFilterSettingsWidgetPrivate::renameFilterClicked()
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    const QString newFilterName = getUniqueFilterName(q->tr("Rename Filter"), currentFilter);
+    if (newFilterName.isEmpty())
+        return;
+
+    const QHelpFilterData oldFilterData = m_filterSettings.filterData(currentFilter);
+    removeFilter(currentFilter);
+    addFilter(newFilterName, oldFilterData);
+
+    if (m_filterSettings.currentFilter() == currentFilter)
+        m_filterSettings.setCurrentFilter(newFilterName);
+}
+
+void QHelpFilterSettingsWidgetPrivate::removeFilterClicked()
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    if (QMessageBox::question(q, q->tr("Remove Filter"),
+                              q->tr("Are you sure you want to remove the \"%1\" filter?")
+                              .arg(currentFilter),
+                              QMessageBox::Yes | QMessageBox::No)
+            != QMessageBox::Yes) {
+        return;
+    }
+
+    removeFilter(currentFilter);
+
+    if (m_filterSettings.currentFilter() == currentFilter)
+        m_filterSettings.setCurrentFilter(QString());
+}
+
+void QHelpFilterSettingsWidgetPrivate::addFilter(const QString &filterName,
+                                                 const QHelpFilterData &filterData)
+{
+    QListWidgetItem *item = new QListWidgetItem(filterName);
+    m_filterSettings.setFilter(filterName, filterData);
+    m_filterToItem.insert(filterName, item);
+    m_itemToFilter.insert(item, filterName);
+    m_ui.filterWidget->insertItem(m_filterToItem.keys().indexOf(filterName), item);
+
+    m_ui.filterWidget->setCurrentItem(item);
+    updateCurrentFilter();
+}
+
+void QHelpFilterSettingsWidgetPrivate::removeFilter(const QString &filterName)
+{
+    QListWidgetItem *item = m_filterToItem.value(filterName);
+    m_itemToFilter.remove(item);
+    m_filterToItem.remove(filterName);
+    delete item;
+
+    m_filterSettings.removeFilter(filterName);
+}
+
+QString QHelpFilterSettingsWidgetPrivate::getUniqueFilterName(const QString &windowTitle,
+                                                              const QString &initialFilterName)
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    QString newFilterName = initialFilterName;
+    while (1) {
+        QFilterNameDialog dialog(q);
+        dialog.setWindowTitle(windowTitle);
+        dialog.setFilterName(newFilterName);
+        if (dialog.exec() == QDialog::Rejected)
+            return QString();
+
+        newFilterName = dialog.filterName();
+        if (!m_filterToItem.contains(newFilterName))
+            break;
+
+        if (QMessageBox::warning(q, q->tr("Filter Exists"),
+                                 q->tr("The filter \"%1\" already exists.")
+                                 .arg(newFilterName),
+                                 QMessageBox::Retry | QMessageBox::Cancel)
+                == QMessageBox::Cancel) {
+            return QString();
+        }
+    }
+
+    return newFilterName;
+}
+
+QString QHelpFilterSettingsWidgetPrivate::suggestedNewFilterName(const QString &initialFilterName) const
+{
+    QString newFilterName = initialFilterName;
+
+    int counter = 1;
+    while (m_filterToItem.contains(newFilterName)) {
+        newFilterName = initialFilterName + QLatin1Char(' ')
+                + QString::number(++counter);
+    }
+
+    return newFilterName;
+}
+
+/*!
+    \class QHelpFilterSettingsWidget
+    \inmodule QtHelp
+    \since 5.15
+    \brief The QHelpFilterSettingsWidget class provides a widget that allows
+    for creating, editing and removing filters.
+
+    The instance of QHelpFilterSettingsWidget may be a part of
+    a preferences dialog. Before showing the dialog, \l setAvailableComponents()
+    and \l setAvailableVersions() should be called, otherwise the filter
+    settings widget will only offer a creation of empty filters,
+    which wouldn't be useful. In addition, \l readSettings should also
+    be called to fill up the filter settings widget with the list of filters
+    already stored in the filter engine. The creation of new filters,
+    modifications to existing filters and removal of unneeded filters are
+    handled by the widget automatically. If you want to store the current
+    state of the widget and apply it to the filter engine e.g. after
+    the user clicked the apply button - call \l applySettings().
+*/
+
+/*!
+    Constructs a filter settings widget with \a parent as parent widget.
+*/
+QHelpFilterSettingsWidget::QHelpFilterSettingsWidget(QWidget *parent)
+    : QWidget(parent)
+    , d_ptr(new QHelpFilterSettingsWidgetPrivate())
+{
+    Q_D(QHelpFilterSettingsWidget);
+    d->q_ptr = this;
+    d->m_ui.setupUi(this);
+
+    // TODO: make resources configurable
+    QString resourcePath = QLatin1String(":/qt-project.org/assistant/images/");
+#ifdef Q_OS_MACOS
+    resourcePath.append(QLatin1String("mac"));
+#else
+    resourcePath.append(QLatin1String("win"));
+#endif
+    d->m_ui.addButton->setIcon(QIcon(resourcePath + QLatin1String("/plus.png")));
+    d->m_ui.removeButton->setIcon(QIcon(resourcePath + QLatin1String("/minus.png")));
+
+    connect(d->m_ui.componentWidget, &QOptionsWidget::optionSelectionChanged,
+            [this](const QStringList &options) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->componentsChanged(options);
+    });
+    connect(d->m_ui.versionWidget, &QOptionsWidget::optionSelectionChanged,
+            [this](const QStringList &options) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->versionsChanged(options);
+    });
+    connect(d->m_ui.filterWidget, &QListWidget::currentItemChanged,
+            this, [this](QListWidgetItem *) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->updateCurrentFilter();
+    });
+    connect(d->m_ui.filterWidget, &QListWidget::itemDoubleClicked,
+            [this](QListWidgetItem *) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->renameFilterClicked();
+    });
+
+    // TODO: repeat these actions on context menu
+    connect(d->m_ui.addButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(QHelpFilterSettingsWidget);
+        d->addFilterClicked();
+    });
+    connect(d->m_ui.renameButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(QHelpFilterSettingsWidget);
+        d->renameFilterClicked();
+    });
+    connect(d->m_ui.removeButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(QHelpFilterSettingsWidget);
+        d->removeFilterClicked();
+    });
+
+    d->m_ui.componentWidget->setNoOptionText(tr("No Component"));
+    d->m_ui.componentWidget->setInvalidOptionText(tr("Invalid Component"));
+    d->m_ui.versionWidget->setNoOptionText(tr("No Version"));
+    d->m_ui.versionWidget->setInvalidOptionText(tr("Invalid Version"));
+}
+
+/*!
+    Destroys the filter settings widget.
+*/
+QHelpFilterSettingsWidget::~QHelpFilterSettingsWidget() = default;
+
+/*!
+    Sets the list of all available components to \a components.
+    \sa QHelpFilterEngine::availableComponents()
+*/
+void QHelpFilterSettingsWidget::setAvailableComponents(const QStringList &components)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    d->m_components = components;
+    d->updateCurrentFilter();
+}
+
+/*!
+    Sets the list of all available version numbers to \a versions.
+    \sa QHelpFilterEngine::availableVersions()
+*/
+void QHelpFilterSettingsWidget::setAvailableVersions(const QList<QVersionNumber> &versions)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    d->m_versions = versions;
+    d->updateCurrentFilter();
+}
+
+/*!
+    Reads the filter settings stored inside \a filterEngine and sets up
+    this filter settings widget accordingly.
+*/
+void QHelpFilterSettingsWidget::readSettings(QHelpFilterEngine *filterEngine)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    const QHelpFilterSettings settings = QHelpFilterSettings::readSettings(filterEngine);
+    d->setFilterSettings(settings);
+}
+
+/*!
+    Writes the filter settings, currently presented in this filter settings
+    widget, to the \a filterEngine. The old settings stored in the filter
+    engine will be overwritten.
+*/
+bool QHelpFilterSettingsWidget::applySettings(QHelpFilterEngine *filterEngine)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    return QHelpFilterSettings::applySettings(filterEngine, d->filterSettings());
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpfiltersettingswidget.h b/src/assistant/help/qhelpfiltersettingswidget.h
new file mode 100644
index 000000000..1b6606054
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettingswidget.h
@@ -0,0 +1,78 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QHELPFILTERSETTINGSWIDGET_H
+#define QHELPFILTERSETTINGSWIDGET_H
+
+#include <QtHelp/qhelp_global.h>
+
+#include <QtWidgets/QWidget>
+
+QT_BEGIN_NAMESPACE
+
+class QVersionNumber;
+
+class QHelpFilterEngine;
+class QHelpFilterSettingsWidgetPrivate;
+
+class QHELP_EXPORT QHelpFilterSettingsWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    QHelpFilterSettingsWidget(QWidget *parent);
+
+    ~QHelpFilterSettingsWidget();
+
+    void setAvailableComponents(const QStringList &components);
+    void setAvailableVersions(const QList<QVersionNumber> &versions);
+
+    // TODO: filterEngine may be moved to c'tor or to setFilterEngine() setter
+    void readSettings(QHelpFilterEngine *filterEngine);
+    bool applySettings(QHelpFilterEngine *filterEngine);
+
+private:
+    QScopedPointer<class QHelpFilterSettingsWidgetPrivate> d_ptr;
+    Q_DECLARE_PRIVATE(QHelpFilterSettingsWidget)
+    Q_DISABLE_COPY_MOVE(QHelpFilterSettingsWidget)
+};
+
+QT_END_NAMESPACE
+
+#endif
+
diff --git a/src/assistant/help/qhelpfiltersettingswidget.ui b/src/assistant/help/qhelpfiltersettingswidget.ui
new file mode 100644
index 000000000..7e16e3f7b
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettingswidget.ui
@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>QHelpFilterSettingsWidget</class>
+ <widget class="QWidget" name="QHelpFilterSettingsWidget">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>347</width>
+    <height>127</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0" colspan="3">
+    <widget class="QLabel" name="filterLabel">
+     <property name="text">
+      <string>Filter</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="3">
+    <widget class="QLabel" name="componentsLabel">
+     <property name="frameShape">
+      <enum>QFrame::NoFrame</enum>
+     </property>
+     <property name="text">
+      <string>Components</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="4">
+    <widget class="QLabel" name="versionsLabel">
+     <property name="text">
+      <string>Versions</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0" colspan="3">
+    <widget class="QListWidget" name="filterWidget"/>
+   </item>
+   <item row="1" column="3" rowspan="2">
+    <widget class="QOptionsWidget" name="componentWidget" native="true"/>
+   </item>
+   <item row="1" column="4" rowspan="2">
+    <widget class="QOptionsWidget" name="versionWidget" native="true"/>
+   </item>
+   <item row="2" column="0">
+    <widget class="QToolButton" name="addButton">
+     <property name="text">
+      <string>Add...</string>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="1">
+    <widget class="QToolButton" name="renameButton">
+     <property name="text">
+      <string>Rename...</string>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="2">
+    <widget class="QToolButton" name="removeButton">
+     <property name="text">
+      <string>Remove</string>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QOptionsWidget</class>
+   <extends>QWidget</extends>
+   <header>qoptionswidget_p.h</header>
+   <container>1</container>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/src/assistant/help/qoptionswidget.cpp b/src/assistant/help/qoptionswidget.cpp
new file mode 100644
index 000000000..21fdfe07a
--- /dev/null
+++ b/src/assistant/help/qoptionswidget.cpp
@@ -0,0 +1,229 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qoptionswidget_p.h"
+
+#include <QtWidgets/QComboBox>
+#include <QtWidgets/QItemDelegate>
+#include <QtWidgets/QListWidget>
+#include <QtWidgets/QVBoxLayout>
+
+QT_BEGIN_NAMESPACE
+
+class ListWidgetDelegate : public QItemDelegate
+{
+public:
+    ListWidgetDelegate(QWidget *w) : QItemDelegate(w), m_widget(w) {}
+
+    static bool isSeparator(const QModelIndex &index) {
+        return index.data(Qt::AccessibleDescriptionRole).toString() == QLatin1String("separator");
+    }
+    static void setSeparator(QListWidgetItem *item) {
+        item->setData(Qt::AccessibleDescriptionRole, QString::fromLatin1("separator"));
+        item->setFlags(item->flags() & ~(Qt::ItemIsSelectable|Qt::ItemIsEnabled));
+    }
+
+protected:
+    void paint(QPainter *painter,
+               const QStyleOptionViewItem &option,
+               const QModelIndex &index) const override {
+        if (isSeparator(index)) {
+            QRect rect = option.rect;
+            if (const QAbstractItemView *view = qobject_cast<const QAbstractItemView*>(option.widget))
+                rect.setWidth(view->viewport()->width());
+            QStyleOption opt;
+            opt.rect = rect;
+            m_widget->style()->drawPrimitive(QStyle::PE_IndicatorToolBarSeparator, &opt, painter, m_widget);
+        } else {
+            QItemDelegate::paint(painter, option, index);
+        }
+    }
+
+    QSize sizeHint(const QStyleOptionViewItem &option,
+                   const QModelIndex &index) const override {
+        if (isSeparator(index)) {
+            int pm = m_widget->style()->pixelMetric(QStyle::PM_DefaultFrameWidth, nullptr, m_widget);
+            return QSize(pm, pm);
+        }
+        return QItemDelegate::sizeHint(option, index);
+    }
+private:
+    QWidget *m_widget;
+};
+
+static QStringList subtract(const QStringList &minuend, const QStringList &subtrahend)
+{
+    QStringList result = minuend;
+    for (const QString &str : subtrahend)
+        result.removeOne(str);
+    return result;
+}
+
+QOptionsWidget::QOptionsWidget(QWidget *parent)
+    : QWidget(parent)
+    , m_noOptionText(tr("No Option"))
+    , m_invalidOptionText(tr("Invalid Option"))
+{
+    m_listWidget = new QListWidget(this);
+    m_listWidget->setItemDelegate(new ListWidgetDelegate(m_listWidget));
+    QVBoxLayout *layout = new QVBoxLayout(this);
+    layout->addWidget(m_listWidget);
+    layout->setContentsMargins(QMargins());
+
+    connect(m_listWidget, &QListWidget::itemChanged, this, &QOptionsWidget::itemChanged);
+}
+
+void QOptionsWidget::clear()
+{
+    setOptions(QStringList(), QStringList());
+}
+
+void QOptionsWidget::setOptions(const QStringList &validOptions,
+                                const QStringList &selectedOptions)
+{
+    m_listWidget->clear();
+    m_optionToItem.clear();
+    m_itemToOption.clear();
+
+    m_validOptions = validOptions;
+    m_validOptions.removeDuplicates();
+    std::sort(m_validOptions.begin(), m_validOptions.end());
+
+    m_selectedOptions = selectedOptions;
+    m_selectedOptions.removeDuplicates();
+    std::sort(m_selectedOptions.begin(), m_selectedOptions.end());
+
+    m_invalidOptions = subtract(m_selectedOptions, m_validOptions);
+    const QStringList validSelectedOptions = subtract(m_selectedOptions, m_invalidOptions);
+    const QStringList validUnselectedOptions = subtract(m_validOptions, m_selectedOptions);
+
+    for (const QString &option : validSelectedOptions)
+        appendItem(option, true, true);
+
+    for (const QString &option : m_invalidOptions)
+        appendItem(option, false, true);
+
+    if ((validSelectedOptions.count() + m_invalidOptions.count())
+            && validUnselectedOptions.count()) {
+        appendSeparator();
+    }
+
+    for (const QString &option : validUnselectedOptions) {
+        appendItem(option, true, false);
+        if (option.isEmpty() && validUnselectedOptions.count() > 1) // special No Option item
+            appendSeparator();
+    }
+}
+
+QStringList QOptionsWidget::validOptions() const
+{
+    return m_validOptions;
+}
+
+QStringList QOptionsWidget::selectedOptions() const
+{
+    return m_selectedOptions;
+}
+
+void QOptionsWidget::setNoOptionText(const QString &text)
+{
+    if (m_noOptionText == text)
+        return;
+
+    m_noOptionText = text;
+
+    // update GUI
+    const auto itEnd = m_optionToItem.constEnd();
+    for (auto it = m_optionToItem.constBegin(); it != itEnd; ++it) {
+        const QString optionName = it.key();
+        if (optionName.isEmpty())
+            it.value()->setText(optionText(optionName, m_validOptions.contains(optionName)));
+    }
+}
+
+void QOptionsWidget::setInvalidOptionText(const QString &text)
+{
+    if (m_invalidOptionText == text)
+        return;
+
+    m_invalidOptionText = text;
+
+    // update GUI
+    for (const QString &option : m_invalidOptions)
+        m_optionToItem.value(option)->setText(optionText(option, false));
+}
+
+QString QOptionsWidget::optionText(const QString &optionName, bool valid) const
+{
+    QString text = optionName;
+    if (optionName.isEmpty())
+        text = QLatin1Char('[') + m_noOptionText + QLatin1Char(']');
+    if (!valid)
+        text += QLatin1String("\t[") + m_invalidOptionText + QLatin1Char(']');
+    return text;
+}
+
+QListWidgetItem *QOptionsWidget::appendItem(const QString &optionName, bool valid, bool selected)
+{
+    QListWidgetItem *optionItem = new QListWidgetItem(optionText(optionName, valid), m_listWidget);
+    optionItem->setCheckState(selected ? Qt::Checked : Qt::Unchecked);
+    m_listWidget->insertItem(m_listWidget->count(), optionItem);
+    m_optionToItem[optionName] = optionItem;
+    m_itemToOption[optionItem] = optionName;
+    return optionItem;
+}
+
+void QOptionsWidget::appendSeparator()
+{
+    QListWidgetItem *separatorItem = new QListWidgetItem(m_listWidget);
+    ListWidgetDelegate::setSeparator(separatorItem);
+    m_listWidget->insertItem(m_listWidget->count(), separatorItem);
+}
+
+void QOptionsWidget::itemChanged(QListWidgetItem *item)
+{
+    const auto it = m_itemToOption.constFind(item);
+    if (it == m_itemToOption.constEnd())
+        return;
+
+    const QString option = *it;
+
+    if (item->checkState() == Qt::Checked && !m_selectedOptions.contains(option)) {
+        m_selectedOptions.append(option);
+        std::sort(m_selectedOptions.begin(), m_selectedOptions.end());
+    } else if (item->checkState() == Qt::Unchecked && m_selectedOptions.contains(option)) {
+        m_selectedOptions.removeOne(option);
+    } else {
+        return;
+    }
+
+    emit optionSelectionChanged(m_selectedOptions);
+}
+
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qoptionswidget_p.h b/src/assistant/help/qoptionswidget_p.h
new file mode 100644
index 000000000..ff075e464
--- /dev/null
+++ b/src/assistant/help/qoptionswidget_p.h
@@ -0,0 +1,76 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QOPTIONSWIDGET_H
+#define QOPTIONSWIDGET_H
+
+#include <QtWidgets/QWidget>
+#include <QtCore/QMap>
+
+QT_BEGIN_NAMESPACE
+
+class QListWidget;
+class QListWidgetItem;
+
+class QOptionsWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    QOptionsWidget(QWidget *parent = nullptr);
+
+    void clear();
+    void setOptions(const QStringList &validOptions,
+                    const QStringList &selectedOptions);
+    QStringList validOptions() const;
+    QStringList selectedOptions() const;
+
+    void setNoOptionText(const QString &text);
+    void setInvalidOptionText(const QString &text);
+
+signals:
+    void optionSelectionChanged(const QStringList &options);
+
+private:
+    QString optionText(const QString &optionName, bool valid) const;
+    QListWidgetItem *appendItem(const QString &optionName, bool valid, bool selected);
+    void appendSeparator();
+    void itemChanged(QListWidgetItem *item);
+
+    QListWidget *m_listWidget = nullptr;
+    QString m_noOptionText;
+    QString m_invalidOptionText;
+    QStringList m_validOptions;
+    QStringList m_invalidOptions;
+    QStringList m_selectedOptions;
+    QMap<QString, QListWidgetItem *> m_optionToItem;
+    QMap<QListWidgetItem *, QString> m_itemToOption;
+};
+
+QT_END_NAMESPACE
+
+#endif  // OPTIONSWIDGET_H