--- a/browser/themes/shared/compacttheme.inc.css
+++ b/browser/themes/shared/compacttheme.inc.css
@@ -227,27 +227,16 @@ toolbar:-moz-lwtheme-darktext {
 
 #nav-bar .toolbarbutton-1:not([type=menu-button]),
 #nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-button,
 #nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-dropmarker {
   padding-top: 2px;
   padding-bottom: 2px;
 }
 
-#back-button:hover:active:not([disabled="true"]) {
-  -moz-image-region: rect(18px, 54px, 36px, 36px);
-}
-
-/* Use smaller back button icon */
-@media (min-resolution: 2dppx) {
-  #back-button:hover:active:not([disabled="true"]) {
-    -moz-image-region: rect(36px, 108px, 72px, 72px);
-  }
-}
-
 /* URL bar and search bar*/
 #urlbar,
 #navigator-toolbox .searchbar-textbox {
   background-color: var(--url-and-searchbar-background-color) !important;
   background-image: none !important;
   color: inherit !important;
   border: 1px solid var(--chrome-nav-bar-controls-border-color) !important;
   box-shadow: none !important;