Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/disp/wddm/VBoxDispD3D.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/disp/wddm/VBoxDispD3D.cpp	(revision 41336)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/disp/wddm/VBoxDispD3D.cpp	(revision 41337)
@@ -5118,4 +5118,6 @@
 
         pAllocation->SurfDesc.cbSize = vboxWddmCalcSize(pAllocation->SurfDesc.pitch, pAllocation->SurfDesc.height, pAllocation->SurfDesc.format);
+
+        pAllocation->SurfDesc.VidPnSourceId = pResource->VidPnSourceId;
     }
 
Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/common/VBoxMPDevExt.h
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/common/VBoxMPDevExt.h	(revision 41336)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/common/VBoxMPDevExt.h	(revision 41337)
@@ -277,5 +277,4 @@
         pAllocation->bVisible = FALSE;
         Assert(pAllocation->SurfDesc.VidPnSourceId == srcId);
-        pAllocation->SurfDesc.VidPnSourceId = srcId;
         pAllocation->bAssigned = TRUE;
     }
Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp	(revision 41336)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp	(revision 41337)
@@ -5284,26 +5284,4 @@
 }
 
-#if 0
-DECLINLINE(bool) vboxWddmCheckForVisiblePrimary(PVBOXMP_DEVEXT pDevExt, PVBOXWDDM_ALLOCATION pAllocation)
-{
-    !!!primary could be of pAllocation->enmType == VBOXWDDM_ALLOC_TYPE_UMD_RC_GENERIC!!!
-    if (pAllocation->enmType != VBOXWDDM_ALLOC_TYPE_STD_SHAREDPRIMARYSURFACE)
-        return false;
-
-    if (!pAllocation->bVisible)
-        return false;
-
-    D3DDDI_VIDEO_PRESENT_SOURCE_ID id = pAllocation->SurfDesc.VidPnSourceId;
-    if (id >= (D3DDDI_VIDEO_PRESENT_SOURCE_ID)VBoxCommonFromDeviceExt(pDevExt)->cDisplays)
-        return false;
-
-    PVBOXWDDM_SOURCE pSource = &pDevExt->aSources[id];
-    if (pSource->pPrimaryAllocation != pAllocation)
-        return false;
-
-    return true;
-}
-#endif
-
 /**
  * DxgkDdiPresent
@@ -5388,6 +5366,4 @@
                                     if (pPresent->DmaBufferPrivateDataSize >= sizeof (VBOXWDDM_DMA_PRIVATEDATA_SHADOW2PRIMARY))
                                     {
-                                        VBOXWDDM_SOURCE *pSource = &pDevExt->aSources[pDstAlloc->SurfDesc.VidPnSourceId];
-//                                        vboxWddmAssignShadow(pDevExt, pSource, pSrcAlloc, pDstAlloc->SurfDesc.VidPnSourceId);
                                         Assert(pPresent->SrcRect.left == pPresent->DstRect.left);
                                         Assert(pPresent->SrcRect.right == pPresent->DstRect.right);