--- a/modules/plugin/test/mochitest/Makefile.in
+++ b/modules/plugin/test/mochitest/Makefile.in
@@ -115,21 +115,21 @@ endif
   utils.js \
   test_npruntime.xul   \
   test_privatemode.xul \
   test_wmode.xul \
   test_bug479979.xul \
   $(NULL)
 
 ifneq ($(MOZ_WIDGET_TOOLKIT),cocoa)
-ifneq ($(OS_ARCH),WINNT)
 _MOCHITEST_FILES += \
   test_visibility.html \
   $(NULL)
 
+ifneq ($(OS_ARCH),WINNT)
 _MOCHICHROME_FILES += \
   test_xulbrowser_plugin_visibility.xul \
   xulbrowser_plugin_visibility.xul \
   plugin_visibility_loader.html \
   $(NULL)
 endif
 endif
 

--- a/modules/plugin/test/mochitest/test_visibility.html
+++ b/modules/plugin/test/mochitest/test_visibility.html
@@ -80,15 +80,24 @@
 
     clearInterval(part4Interval);
 
     ok(true, "Plugin became invisible again.");
     p.setColor('FF00FF00');
     setTimeout(SimpleTest.finish, 500);
     // wait to make sure we don't actually paint
   }
+
+  function inPaint() {
+    // We're actually in the middle of painting the plugin so don't do anything
+    // complex here, for the sake of cases where async plugin painting isn't
+    // enabled yet
+    setTimeout(didPaint, 0);
+    // Don't run that didPaint callback again
+    didPaint = function() {};
+  }
   </script>
 
-  <embed id="theplugin" class="hidden" type="application/x-test" drawmode="solid" color="FFFF0000" paintscript="setTimeout(didpaint, 0)"></embed>
+  <embed id="theplugin" class="hidden" type="application/x-test" drawmode="solid" color="FFFF0000" paintscript="inPaint()"></embed>
   
   <script type="application/javascript">
   var p = document.getElementById('theplugin');
   </script>