Identify XButton1|2 release events when mouse is moving.

X11 has no special state for XButton1 and XButton2, so we need
to look at the global `mouseButtonState` and restore the buttons
after a mouse move.

Task-number: QTBUG-40148
Change-Id: I789f32b344cf7902b1c7aa6b7da7f20f32602be2
Reviewed-by: Alexander Volkov <a.volkov@rusbitech.ru>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gui/kernel/qapplication_x11.cpp b/src/gui/kernel/qapplication_x11.cpp
index ba8bc1a624..a198fd931b 100644
--- a/src/gui/kernel/qapplication_x11.cpp
+++ b/src/gui/kernel/qapplication_x11.cpp
@@ -4189,6 +4189,12 @@ static Qt::MouseButtons translateMouseButtons(int s)
         ret |= Qt::MidButton;
     if (s & Button3Mask)
         ret |= Qt::RightButton;
+    // X11 has no special state for XButton1 and XButton2, so we need to use
+    // the global state maintained between press and release.
+    if (mouseButtonState.testFlag(Qt::XButton1))
+        ret |= Qt::XButton1;
+    if (mouseButtonState.testFlag(Qt::XButton2))
+        ret |= Qt::XButton2;
     return ret;
 }