We might sometimes end up with an empty copy because of clipping. Make sure
we don't waste more CPU cycles on these.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4229 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/unix/xserver/hw/vnc/vncHooks.cc b/unix/xserver/hw/vnc/vncHooks.cc
index 2f7b4a2..52ef42a 100644
--- a/unix/xserver/hw/vnc/vncHooks.cc
+++ b/unix/xserver/hw/vnc/vncHooks.cc
@@ -410,7 +410,8 @@
 
   (*pScreen->CopyWindow) (pWin, ptOldOrg, pOldRegion);
 
-  vncHooksScreen->desktop->add_copied(copied.reg, dx, dy);
+  if (REGION_NOTEMPTY(pScreen, copied.reg))
+    vncHooksScreen->desktop->add_copied(copied.reg, dx, dy);
 
   SCREEN_REWRAP(CopyWindow);
 }