diff --git a/mi/mioverlay.c b/mi/mioverlay.c
index 23cc2b366..0c1d79d70 100644
--- a/mi/mioverlay.c
+++ b/mi/mioverlay.c
@@ -54,3 +54,59 @@ typedef struct {
     Bool underlayMarked;
     Bool copyUnderlay;
 } miOverlayScreenRec, *miOverlayScreenPtr;
+
+static DevPrivateKeyRec miOverlayWindowKeyRec;
+
+#define miOverlayWindowKey (&miOverlayWindowKeyRec)
+
+static void MarkUnderlayWindow(WindowPtr);
+
+#define MIOVERLAY_GET_WINDOW_PRIVATE(pWin) ((miOverlayWindowPtr) \
+	dixLookupPrivate(&(pWin)->devPrivates, miOverlayWindowKey))
+#define MIOVERLAY_GET_WINDOW_TREE(pWin) \
+	(MIOVERLAY_GET_WINDOW_PRIVATE(pWin)->tree)
+
+#define MARK_UNDERLAY(w) MarkUnderlayWindow(w)
+
+/*  We need this as an addition since the xf86 common code doesn't
+    know about the second tree which is static to this file.  */
+
+void
+miOverlaySetRootClip(ScreenPtr pScreen, Bool enable)
+{
+    WindowPtr pRoot = pScreen->root;
+    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pRoot);
+
+    MARK_UNDERLAY(pRoot);
+
+    if (enable) {
+        BoxRec box;
+
+        box.x1 = 0;
+        box.y1 = 0;
+        box.x2 = pScreen->width;
+        box.y2 = pScreen->height;
+
+        RegionReset(&pTree->borderClip, &box);
+    }
+    else
+        RegionEmpty(&pTree->borderClip);
+
+    RegionBreak(&pTree->clipList);
+}
+
+/****************************************************************/
+
+static void
+MarkUnderlayWindow(WindowPtr pWin)
+{
+    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
+
+    if (pTree->valdata)
+        return;
+    pTree->valdata =
+        (miOverlayValDataPtr) XNFalloc(sizeof(miOverlayValDataRec));
+    pTree->valdata->oldAbsCorner.x = pWin->drawable.x;
+    pTree->valdata->oldAbsCorner.y = pWin->drawable.y;
+    pTree->valdata->borderVisible = NullRegion;
+}
diff --git a/mi/mioverlay.h b/mi/mioverlay.h
index 857491dd3..68a88260a 100644
--- a/mi/mioverlay.h
+++ b/mi/mioverlay.h
@@ -9,4 +9,6 @@
 typedef void (*miOverlayTransFunc) (ScreenPtr, int, BoxPtr);
 typedef Bool (*miOverlayInOverlayFunc) (WindowPtr);
 
+extern _X_EXPORT void miOverlaySetRootClip(ScreenPtr, Bool);
+
 #endif                          /* __MIOVERLAY_H */