Index: /trunk/src/VBox/Frontends/VirtualBox/src/runtime/fullscreen/UIMachineWindowFullscreen.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/runtime/fullscreen/UIMachineWindowFullscreen.cpp	(revision 56933)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/runtime/fullscreen/UIMachineWindowFullscreen.cpp	(revision 56934)
@@ -263,6 +263,8 @@
     AssertPtrReturnVoid(m_pMiniToolBar);
     {
+#ifdef Q_WS_X11
         /* Make sure mini-toolbar is always-on-top of machine-window: */
         VBoxGlobal::setTransientFor(m_pMiniToolBar, this);
+#endif /* Q_WS_X11 */
         /* Configure mini-toolbar: */
         m_pMiniToolBar->addMenus(actionPool()->menus());
Index: /trunk/src/VBox/Frontends/VirtualBox/src/runtime/seamless/UIMachineWindowSeamless.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/runtime/seamless/UIMachineWindowSeamless.cpp	(revision 56933)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/runtime/seamless/UIMachineWindowSeamless.cpp	(revision 56934)
@@ -146,6 +146,8 @@
     AssertPtrReturnVoid(m_pMiniToolBar);
     {
+#ifdef Q_WS_X11
         /* Make sure mini-toolbar is always-on-top of machine-window: */
         VBoxGlobal::setTransientFor(m_pMiniToolBar, this);
+#endif /* Q_WS_X11 */
         /* Configure mini-toolbar: */
         m_pMiniToolBar->addMenus(actionPool()->menus());