Workaround Qtbug where QAbstractScrollArea::mouseMoveEvent(...) is called falsely...

diff --git a/src/frontends/qt/GuiWorkArea.cpp b/src/frontends/qt/GuiWorkArea.cpp
index fa40a5aa10017bcea5c2832f9b1578ad490381b1..23d6efa54100d1a0aa2360309c81514c67f17ac8 100644 (file)
--- a/src/frontends/qt/GuiWorkArea.cpp
+++ b/src/frontends/qt/GuiWorkArea.cpp
@@ -852,6 +852,9 @@ void GuiWorkArea::mouseReleaseEvent(QMouseEvent * e)
 
        FuncRequest const cmd(LFUN_MOUSE_RELEASE, e->x(), e->y(),
                        q_button_state(e->button()), q_key_state(e->modifiers()));
+#if (QT_VERSION > QT_VERSION_CHECK(5,10,1))
+       d->synthetic_mouse_event_.cmd = cmd; // QtBug QAbstractScrollArea::mouseMoveEvent
+#endif
        d->dispatch(cmd);
        e->accept();
 }
@@ -859,6 +862,19 @@ void GuiWorkArea::mouseReleaseEvent(QMouseEvent * e)
 
 void GuiWorkArea::mouseMoveEvent(QMouseEvent * e)
 {
+#if (QT_VERSION > QT_VERSION_CHECK(5,10,1))
+       // cancel the event if the coordinates didn't change, this is due to QtBug
+       // QAbstractScrollArea::mouseMoveEvent, the event is triggered falsely when quickly
+       // double tapping a touchpad. To test: try to select a word by quickly double tapping
+       // on a touchpad while hovering the cursor over that word in the work area.
+       // This bug does not occur on Qt versions 5.10.1 and below. Only Windows seems to be affected.
+       // ML thread: https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg211699.html
+       // Qt bugtracker: https://bugreports.qt.io/browse/QTBUG-85431
+       if (e->x() == d->synthetic_mouse_event_.cmd.x() && // QtBug QAbstractScrollArea::mouseMoveEvent
+                       e->y() == d->synthetic_mouse_event_.cmd.y()) // QtBug QAbstractScrollArea::mouseMoveEvent
+               return; // QtBug QAbstractScrollArea::mouseMoveEvent
+#endif
+
        // we kill the triple click if we move
        doubleClickTimeout();
        FuncRequest cmd(LFUN_MOUSE_MOTION, e->x(), e->y(),