Windows: Post drag events for the window on which the drop site was registered.

Remove findDragOverWindow(); no longer try to find the window under cursor
since that would require synthesizing drag leave events. This is left to the
DnD handling of QWidgetWindow, which searches the child which accepts drops.

Task-number: QTBUG-33635

Change-Id: I844041bb862bb0382147be4e28f880a26843c453
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

2 files changed, 6 insertions, 18 deletions

diff --git a/src/plugins/platforms/windows/qwindowsdrag.cpp b/src/plugins/platforms/windows/qwindowsdrag.cpp
index 8f3ccdc0be..60c3daff23 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.cpp
+++ b/src/plugins/platforms/windows/qwindowsdrag.cpp
@@ -673,14 +673,6 @@ QWindowsOleDropTarget::Release(void)
     return m_refs;
 }
 
-QWindow *QWindowsOleDropTarget::findDragOverWindow(const POINTL &pt) const
-{
-    if (QWindowsWindow *child =
-            QWindowsWindow::baseWindowOf(m_window)->childAtScreenPoint(QPoint(pt.x, pt.y)))
-            return child->window();
-    return m_window;
-}
-
 void QWindowsOleDropTarget::handleDrag(QWindow *window, DWORD grfKeyState,
                                        const QPoint &point, LPDWORD pdwEffect)
 {
@@ -735,10 +727,9 @@ QWindowsOleDropTarget::DragOver(DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect)
     if (IDropTargetHelper* dh = QWindowsDrag::instance()->dropHelper())
         dh->DragOver(reinterpret_cast<POINT*>(&pt), *pdwEffect);
 
-    QWindow *dragOverWindow = findDragOverWindow(pt);
-    qCDebug(lcQpaMime) << __FUNCTION__ << "widget=" << dragOverWindow << " key=" << grfKeyState
+    qCDebug(lcQpaMime) << __FUNCTION__ << "m_window" << m_window << "key=" << grfKeyState
         << "pt=" << pt.x << pt.y;
-    const QPoint tmpPoint = QWindowsGeometryHint::mapFromGlobal(dragOverWindow, QPoint(pt.x,pt.y));
+    const QPoint tmpPoint = QWindowsGeometryHint::mapFromGlobal(m_window, QPoint(pt.x,pt.y));
     // see if we should compress this event
     if ((tmpPoint == m_lastPoint || m_answerRect.contains(tmpPoint))
         && m_lastKeyState == grfKeyState) {
@@ -747,7 +738,7 @@ QWindowsOleDropTarget::DragOver(DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect)
         return NOERROR;
     }
 
-    handleDrag(dragOverWindow, grfKeyState, tmpPoint, pdwEffect);
+    handleDrag(m_window, grfKeyState, tmpPoint, pdwEffect);
     return NOERROR;
 }
 
@@ -774,12 +765,10 @@ QWindowsOleDropTarget::Drop(LPDATAOBJECT pDataObj, DWORD grfKeyState,
     if (IDropTargetHelper* dh = QWindowsDrag::instance()->dropHelper())
         dh->Drop(pDataObj, reinterpret_cast<POINT*>(&pt), *pdwEffect);
 
-    QWindow *dropWindow = findDragOverWindow(pt);
-
     qCDebug(lcQpaMime) << __FUNCTION__ << ' ' << m_window
-        << " on " << dropWindow << " keys=" << grfKeyState << " pt=" << pt.x << ',' << pt.y;
+        << "keys=" << grfKeyState << "pt=" << pt.x << ',' << pt.y;
 
-    m_lastPoint = QWindowsGeometryHint::mapFromGlobal(dropWindow, QPoint(pt.x,pt.y));
+    m_lastPoint = QWindowsGeometryHint::mapFromGlobal(m_window, QPoint(pt.x,pt.y));
     // grfKeyState does not all ways contain button state in the drop so if
     // it doesn't then use the last known button state;
     if ((grfKeyState & KEY_STATE_BUTTON_MASK) == 0)
@@ -789,7 +778,7 @@ QWindowsOleDropTarget::Drop(LPDATAOBJECT pDataObj, DWORD grfKeyState,
     QWindowsDrag *windowsDrag = QWindowsDrag::instance();
 
     const QPlatformDropQtResponse response =
-        QWindowSystemInterface::handleDrop(dropWindow, windowsDrag->dropData(), m_lastPoint,
+        QWindowSystemInterface::handleDrop(m_window, windowsDrag->dropData(), m_lastPoint,
                                            translateToQDragDropActions(*pdwEffect));
 
     if (response.isAccepted()) {
diff --git a/src/plugins/platforms/windows/qwindowsdrag.h b/src/plugins/platforms/windows/qwindowsdrag.h
index 33da4d6cc5..4f758fbf3f 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.h
+++ b/src/plugins/platforms/windows/qwindowsdrag.h
@@ -74,7 +74,6 @@ public:
     STDMETHOD(Drop)(LPDATAOBJECT pDataObj, DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect);
 
 private:
-    inline QWindow *findDragOverWindow(const POINTL &pt) const;
     void handleDrag(QWindow *window, DWORD grfKeyState, const QPoint &, LPDWORD pdwEffect);
 
     ULONG m_refs;