Ensure the button state is correct when creating a QWheelEvent on Mac.

On Mac when we receive a scrollWheel event on Carbon or Cocoa then
we need to use QApplication::mouseButtons() in order to ensure the
QWheelEvent has the right button states set.  This is because the
buttons state information is not passed in the native event at all.

Reviewed-by: MortenS

2 files changed, 5 insertions, 2 deletions

diff --git a/src/gui/kernel/qapplication_mac.mm b/src/gui/kernel/qapplication_mac.mm
index 22a0959..688e51f 100644
--- a/src/gui/kernel/qapplication_mac.mm
+++ b/src/gui/kernel/qapplication_mac.mm
@@ -1687,7 +1687,10 @@ QApplicationPrivate::globalEventProcessor(EventHandlerCallRef er, EventRef event
             UInt32 mac_buttons = 0;
             GetEventParameter(event, kEventParamMouseChord, typeUInt32, 0,
                               sizeof(mac_buttons), 0, &mac_buttons);
-            buttons = qt_mac_get_buttons(mac_buttons);
+            if (ekind != kEventMouseWheelMoved)
+                buttons = qt_mac_get_buttons(mac_buttons);
+            else
+                buttons = QApplication::mouseButtons();
         }
 
         int wheel_deltaX = 0;
diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index 000f223..ddd8ca6 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -779,7 +779,7 @@ extern "C" {
     NSPoint localPoint = [self convertPoint:windowPoint fromView:nil];
     QPoint qlocal = QPoint(localPoint.x, flipYCoordinate(localPoint.y));
     QPoint qglobal = QPoint(globalPoint.x, flipYCoordinate(globalPoint.y));
-    Qt::MouseButton buttons = cocoaButton2QtButton([theEvent buttonNumber]);
+    Qt::MouseButtons buttons = QApplication::mouseButtons();
     bool wheelOK = false;
     Qt::KeyboardModifiers keyMods = qt_cocoaModifiers2QtModifiers([theEvent modifierFlags]);
     QWidget *widgetToGetMouse = qwidget;