diff --git a/libvncserver/main.c b/libvncserver/main.c
index b6bd930..6aa82d3 100644
--- a/libvncserver/main.c
+++ b/libvncserver/main.c
@@ -894,6 +894,7 @@ rfbScreenInfoPtr rfbGetScreen(int* argc,char** argv,
    screen->setTranslateFunction = rfbSetTranslateFunction;
    screen->newClientHook = rfbDefaultNewClientHook;
    screen->displayHook = NULL;
+   screen->displayFinishedHook = NULL;
    screen->getKeyboardLedStateHook = NULL;
 
    /* initialize client list and iterator mutex */
diff --git a/libvncserver/rfbserver.c b/libvncserver/rfbserver.c
index 465d767..48fd74a 100644
--- a/libvncserver/rfbserver.c
+++ b/libvncserver/rfbserver.c
@@ -2446,9 +2446,14 @@ rfbSendFramebufferUpdate(rfbClientPtr cl,
       fu->nRects = Swap16IfLE(1);
       cl->ublen = sz_rfbFramebufferUpdateMsg;
       if (!rfbSendNewFBSize(cl, cl->scaledScreen->width, cl->scaledScreen->height)) {
+	if(cl->screen->displayFinishedHook)
+	  cl->screen->displayFinishedHook(cl, FALSE);
         return FALSE;
       }
-      return rfbSendUpdateBuf(cl);
+      result = rfbSendUpdateBuf(cl);
+      if(cl->screen->displayFinishedHook)
+	cl->screen->displayFinishedHook(cl, result);
+      return result;
     }
     
     /*
@@ -2564,6 +2569,8 @@ rfbSendFramebufferUpdate(rfbClientPtr cl,
        !sendSupportedMessages && !sendSupportedEncodings && !sendServerIdentity) {
       sraRgnDestroy(updateRegion);
       UNLOCK(cl->updateMutex);
+      if(cl->screen->displayFinishedHook)
+	cl->screen->displayFinishedHook(cl, TRUE);
       return TRUE;
     }
 
@@ -2841,6 +2848,9 @@ updateFailed:
         sraRgnReleaseIterator(i);
     sraRgnDestroy(updateRegion);
     sraRgnDestroy(updateCopyRegion);
+
+    if(cl->screen->displayFinishedHook)
+      cl->screen->displayFinishedHook(cl, result);
     return result;
 }
 
diff --git a/rfb/rfb.h b/rfb/rfb.h
index a03ab21..006cc2e 100644
--- a/rfb/rfb.h
+++ b/rfb/rfb.h
@@ -136,6 +136,7 @@ typedef rfbBool (*rfbSetTranslateFunctionProcPtr)(struct _rfbClientRec* cl);
 typedef rfbBool (*rfbPasswordCheckProcPtr)(struct _rfbClientRec* cl,const char* encryptedPassWord,int len);
 typedef enum rfbNewClientAction (*rfbNewClientHookPtr)(struct _rfbClientRec* cl);
 typedef void (*rfbDisplayHookPtr)(struct _rfbClientRec* cl);
+typedef void (*rfbDisplayFinishedHookPtr)(struct _rfbClientRec* cl, int result);
 /* support the capability to view the caps/num/scroll states of the X server */
 typedef int  (*rfbGetKeyboardLedStateHookPtr)(struct _rfbScreenInfo* screen);
 /* If x==1 and y==1 then set the whole display
@@ -352,6 +353,9 @@ typedef struct _rfbScreenInfo
 
     /* command line authorization of file transfers */
     rfbBool permitFileTransfer;
+
+    /* displayFinishedHook is called just after a frame buffer update */
+    rfbDisplayFinishedHookPtr displayFinishedHook;
 } rfbScreenInfo, *rfbScreenInfoPtr;