diff -up mutter-3.8.4/src/compositor/meta-texture-tower.c.texture-tower mutter-3.8.4/src/compositor/meta-texture-tower.c
--- mutter-3.8.4/src/compositor/meta-texture-tower.c.texture-tower	2014-09-29 15:07:00.955634201 -0400
+++ mutter-3.8.4/src/compositor/meta-texture-tower.c	2014-09-29 15:08:01.656005996 -0400
@@ -562,6 +562,9 @@ texture_tower_revalidate (MetaTextureTow
 {
   if (!texture_tower_revalidate_fbo (tower, level))
     texture_tower_revalidate_client (tower, level);
+
+  tower->invalid[level].x1 = tower->invalid[level].x2 = 0;
+  tower->invalid[level].y1 = tower->invalid[level].y2 = 0;
 }
 
 /**