--- a/toolkit/themes/shared/extensions/extensions.inc.css
+++ b/toolkit/themes/shared/extensions/extensions.inc.css
@@ -1049,19 +1049,25 @@ button.button-link:hover {
 button.button-link:not([disabled="true"]):active:hover {
   background-color: transparent;
   color: #ff9500;
   text-decoration: none;
 }
 
 .addon-control.replacement {
   background-color: #0095dd;
+  border-color: #0095dd;
   color: #FFF;
 }
 
+.addon-control.replacement:hover {
+  background-color: #006b9d;
+  border-color: #006b9d;
+}
+
 /*** telemetry experiments ***/
 
 #detail-experiment-container {
   font-size: 80%;
   margin-bottom: 1em;
 }
 
 #detail-experiment-bullet-container,