--- a/browser/themes/shared/customizableui/customizeMode.inc.css
+++ b/browser/themes/shared/customizableui/customizeMode.inc.css
@@ -232,16 +232,20 @@ toolbarpaletteitem[place="toolbar"] {
 #customization-palette:not([hidden]) {
   margin-bottom: 20px;
 }
 
 #customization-palette .toolbarbutton-1 {
   fill: currentColor;
 }
 
+#customization-palette .toolbarbutton-1[checked="true"]:not([disabled="true"]) {
+  color: inherit
+}
+
 toolbarpaletteitem[place="palette"]:-moz-focusring,
 toolbarpaletteitem[place="panel"]:-moz-focusring,
 toolbarpaletteitem[place="toolbar"]:-moz-focusring {
   outline-width: 0;
 }
 
 toolbarpaletteitem[place="palette"]:not([mousedown="true"]):-moz-focusring,
 toolbarpaletteitem[place="panel"]:not([mousedown="true"]):-moz-focusring,