DragDrop operations sometimes don't end properly

Sometimes a Drag/Drop operation doesn't finish after the left mouse button has been released. Instead of a Drop a small movement of the draggable image occurs. This is the problem not only of my project but of almost all of the drag/drop QT examples. Having done some digging I found out that the QOleDropSource::QueryContinueDrag function (file qdnd_win.cpp) doesn't always receive a proper grfKeyState value (similar to WinCE). Making the same check as for WinCE solves the problem. These are the changed lines:

    if (fEscapePressed) {
        return ResultFromScode(DRAGDROP_S_CANCEL);
//    } else if (!(grfKeyState & (MK_LBUTTON|MK_MBUTTON|MK_RBUTTON))) {
    // grfKeyState is broken on some WinXP, therefore need to check
    // the state manually
    } else if ((GetAsyncKeyState(VK_LBUTTON) == 0) &&
            (GetAsyncKeyState(VK_MBUTTON) == 0) &&
            (GetAsyncKeyState(VK_RBUTTON) == 0)) {
        return ResultFromScode(DRAGDROP_S_DROP);
    } else {
#if defined(Q_OS_WINCE)

Best regards