Index: /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMachineView.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMachineView.cpp	(revision 54075)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMachineView.cpp	(revision 54076)
@@ -549,4 +549,7 @@
                                           (uint32_t)(dScaleFactor * VBOX_OGL_SCALE_FACTOR_MULTIPLIER));
 
+        /* Take backing scale-factor into account: */
+        m_pFrameBuffer->setBackingScaleFactor(darwinBackingScaleFactor(machineWindow()));
+
         /* Take unscaled HiDPI output mode into account: */
         const bool fUseUnscaledHiDPIOutput = gEDataManager->useUnscaledHiDPIOutput(vboxGlobal().managedVMUuid());
@@ -983,5 +986,5 @@
      * we should take the backing-scale-factor into account.
      * See also viewportToContents()... */
-    if (gEDataManager->useUnscaledHiDPIOutput(vboxGlobal().managedVMUuid()))
+    if (frameBuffer()->useUnscaledHiDPIOutput())
     {
         const double dBackingScaleFactor = frameBuffer()->backingScaleFactor();
@@ -1011,5 +1014,5 @@
      * we should take the backing-scale-factor into account.
      * See also updateSliders()... */
-    if (gEDataManager->useUnscaledHiDPIOutput(vboxGlobal().managedVMUuid()))
+    if (frameBuffer()->useUnscaledHiDPIOutput())
     {
         const double dBackingScaleFactor = frameBuffer()->backingScaleFactor();
@@ -1463,5 +1466,5 @@
 #ifdef Q_WS_MAC
     /* Take the backing-scale-factor into account: */
-    if (gEDataManager->useUnscaledHiDPIOutput(vboxGlobal().managedVMUuid()))
+    if (frameBuffer()->useUnscaledHiDPIOutput())
     {
         const double dBackingScaleFactor = frameBuffer()->backingScaleFactor();
@@ -1479,5 +1482,5 @@
 #ifdef Q_WS_MAC
     /* Take the backing-scale-factor into account: */
-    if (gEDataManager->useUnscaledHiDPIOutput(vboxGlobal().managedVMUuid()))
+    if (frameBuffer()->useUnscaledHiDPIOutput())
     {
         const double dBackingScaleFactor = frameBuffer()->backingScaleFactor();
Index: /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMouseHandler.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMouseHandler.cpp	(revision 54075)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMouseHandler.cpp	(revision 54076)
@@ -944,5 +944,5 @@
 #ifdef Q_WS_MAC
             /* Take the backing-scale-factor into account: */
-            if (gEDataManager->useUnscaledHiDPIOutput(vboxGlobal().managedVMUuid()))
+            if (pFrameBuffer->useUnscaledHiDPIOutput())
             {
                 const double dBackingScaleFactor = pFrameBuffer->backingScaleFactor();