--- a/browser/themes/shared/incontentprefs/siteDataSettings.css
+++ b/browser/themes/shared/incontentprefs/siteDataSettings.css
@@ -4,16 +4,21 @@
 
 /**
  * Site Data - Settings dialog
  */
 #sitesList {
   min-height: 20em;
 }
 
+/* Show selected items in high contrast mode. */
+#sitesList > richlistitem[selected] {
+  outline: 1px solid transparent;
+}
+
 #sitesList > richlistitem > hbox,
 .item-box > label {
   -moz-box-flex: 1;
 }
 
 .item-box {
   padding: 5px 8px;
   -moz-box-align: center;