Index: /trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c
===================================================================
--- /trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c	(revision 43308)
+++ /trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c	(revision 43309)
@@ -1114,4 +1114,11 @@
                      pScrn->frameY0))
         return FALSE;
+    /* Save the size in case we need to re-set it later. */
+    pVBox->FBSize.cx = pScrn->currentMode->HDisplay;
+    pVBox->FBSize.cy = pScrn->currentMode->VDisplay;
+    pVBox->aScreenLocation[0].cx = pScrn->currentMode->HDisplay;
+    pVBox->aScreenLocation[0].cy = pScrn->currentMode->VDisplay;
+    pVBox->aScreenLocation[0].x = pScrn->frameX0;
+    pVBox->aScreenLocation[0].y = pScrn->frameY0;
     /* And make sure that a non-current dynamic mode is at the front of the
      * list */