--- a/browser/themes/linux/searchbar.css
+++ b/browser/themes/linux/searchbar.css
@@ -261,18 +261,17 @@ menuitem[cmd="cmd_clearhistory"][disable
   border-top: 1px solid var(--panel-separator-color);
 }
 
 .addengine-item[selected] {
   background-color: Highlight;
   color: HighlightText;
 }
 
-.addengine-item[type=menu][selected],
-.addengine-item[type=menu][open] {
+.addengine-item[type=menu][selected] {
   color: inherit;
   background-color: var(--arrowpanel-dimmed-further);
 }
 
 .addengine-icon {
   width: 16px;
 }
 

--- a/browser/themes/windows/searchbar.css
+++ b/browser/themes/windows/searchbar.css
@@ -254,18 +254,17 @@
   border-top: 1px solid var(--panel-separator-color);
 }
 
 .addengine-item[selected] {
   background-color: Highlight;
   color: HighlightText;
 }
 
-.addengine-item[type=menu][selected],
-.addengine-item[type=menu][open] {
+.addengine-item[type=menu][selected] {
   color: inherit;
   background-color: var(--arrowpanel-dimmed-further);
 }
 
 .addengine-icon {
   width: 16px;
 }