--- a/toolkit/themes/osx/global/popup.css
+++ b/toolkit/themes/osx/global/popup.css
@@ -46,17 +46,16 @@ panel[type="arrow"][side="right"] {
   margin-top: -25px;
   margin-bottom: -25px;
 }
 
 .panel-arrowcontent {
   -moz-appearance: none;
   background: var(--panel-arrowcontent-background);
   border-radius: var(--panel-arrowcontent-border-radius);
-  box-shadow: 0 0 0 1px hsla(210,4%,10%,.05);
   color: var(--panel-arrowcontent-color);
   border: var(--panel-arrowcontent-border);
   padding: var(--panel-arrowcontent-padding);
   margin: 1px;
 }
 
 .panel-arrow[side="top"] {
   list-style-image: url("chrome://global/skin/arrow/panelarrow-vertical.png");