diff --git a/layout/xul/test/test_bug477754.xul b/layout/xul/test/test_bug477754.xul
index 111c5b805d4..f72b1fffa5d 100644
--- a/layout/xul/test/test_bug477754.xul
+++ b/layout/xul/test/test_bug477754.xul
@@ -38,8 +38,8 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=477754
     }, false);
 
     function doTest() {
-      is(Math.round(testAnchor.getBoundingClientRect().right) -
-         Math.round(testPopup.getBoundingClientRect().right), 10,
+      is(Math.round(testAnchor.getBoundingClientRect().right -
+                    testPopup.getBoundingClientRect().right), 10,
          "RTL popup's right offset should be equal to the x offset passed to openPopup");
       testPopup.hidePopup();
       SimpleTest.finish();
diff --git a/toolkit/themes/osx/global/global.css b/toolkit/themes/osx/global/global.css
index d649a584fd4..c5777279dcc 100644
--- a/toolkit/themes/osx/global/global.css
+++ b/toolkit/themes/osx/global/global.css
@@ -176,10 +176,10 @@ separator.groove[orient="vertical"] {
 description,
 label {
   cursor: default;
-  /* FIXME: On Windows and Linux, we're using -moz-margin-end: 5px, but for
-            unknown reasons this breaks test_bug477754.xul on OS X.
-            See bug 1169606. */
-  margin: 1px 6px 2px;
+  margin-top: 1px;
+  margin-bottom: 2px;
+  -moz-margin-start: 6px;
+  -moz-margin-end: 5px;
 }
 
 description {