--- a/browser/themes/shared/UITour.inc.css
+++ b/browser/themes/shared/UITour.inc.css
@@ -3,19 +3,21 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 %endif
 
 /* UI Tour */
 
 #UITourHighlightContainer {
   -moz-appearance: none;
+  -moz-window-shadow: none;
   border: none;
   background-color: transparent;
-  /* This is a buffer to compensate for the movement in the "wobble" effect */
+  /* This is a buffer to compensate for the movement in the "wobble" effect,
+     and for the box-shadow of #UITourHighlight. */
   padding: 4px;
 }
 
 #UITourHighlight {
   background-image: radial-gradient(50% 100%, rgba(0,149,220,0.4) 50%, rgba(0,149,220,0.6) 100%);
   border-radius: 40px;
   border: 1px solid white;
   /* The box-shadow opacity needs to be < 0.5 so it doesn't appear at 100% opacity