--- a/layout/tools/reftest/reftest-content.js
+++ b/layout/tools/reftest/reftest-content.js
@@ -577,17 +577,21 @@ function WaitForTestEnd(contentRootEleme
     // change from returning true to returning false is monitored via some kind
     // of event listener which eventually calls this function.
     function MakeProgress() {
         if (state >= STATE_COMPLETED) {
             LogInfo("MakeProgress: STATE_COMPLETED");
             return;
         }
 
-        FlushRendering();
+        // We don't need to flush styles any more when we are in the state
+        // after reftest-wait has removed.
+        if (state != STATE_WAITING_TO_FINISH) {
+          FlushRendering();
+        }
 
         switch (state) {
         case STATE_WAITING_TO_FIRE_INVALIDATE_EVENT: {
             LogInfo("MakeProgress: STATE_WAITING_TO_FIRE_INVALIDATE_EVENT");
             if (shouldWaitForExplicitPaintWaiters() || shouldWaitForPendingPaints()) {
                 gFailureReason = "timed out waiting for pending paint count to reach zero";
                 if (shouldWaitForExplicitPaintWaiters()) {
                     gFailureReason += " (waiting for MozPaintWaitFinished)";