Fixes a potential crash when changing system palette with QGtkStyle

The problem was that we installed an eventfilter regardless if the
gtk symbols were defined or not. Instead we now initialize and
check for the symbols before we install the filter.

Task-number: 254342
Reviewed-by: ogoffart

1 files changed, 7 insertions, 6 deletions

diff --git a/src/gui/styles/qgtkstyle.cpp b/src/gui/styles/qgtkstyle.cpp
index ca71da2f1d..86653df8da 100644
--- a/src/gui/styles/qgtkstyle.cpp
+++ b/src/gui/styles/qgtkstyle.cpp
@@ -140,10 +140,7 @@ static const char * const dock_widget_restore_xpm[] =
 class QGtkStyleFilter : public QObject
 {
 public:
-    QGtkStyleFilter() {
-        qApp->installEventFilter(this);
-    }
-
+    QGtkStyleFilter() {}
 private:
     bool eventFilter(QObject *obj, QEvent *e);
 };
@@ -167,7 +164,12 @@ class QGtkStylePrivate : public QCleanlooksStylePrivate
 public:
     QGtkStylePrivate()
             : QCleanlooksStylePrivate()
-    {}
+    {
+        QGtk::initGtkWidgets();
+        if (QGtk::isThemeAvailable())
+            qApp->installEventFilter(&filter);
+
+    }
     QGtkStyleFilter filter;
 };
 
@@ -243,7 +245,6 @@ static QString uniqueName(const QString &key, const QStyleOption *option, const
 QGtkStyle::QGtkStyle()
     : QCleanlooksStyle(*new QGtkStylePrivate)
 {
-    QGtk::initGtkWidgets();
 }
 
 /*!