diff --git a/chrome/skin/default/zotero/overlay.css b/chrome/skin/default/zotero/overlay.css
index e6a509efff..ea6fa6d049 100644
--- a/chrome/skin/default/zotero/overlay.css
+++ b/chrome/skin/default/zotero/overlay.css
@@ -12,6 +12,7 @@
 {
 	margin-left: 10px;
 	margin-right: 10px;
+	-moz-appearance: none;
 }
 #zotero-status-bar-icon[compact="true"], #zotero-addon-bar-icon[compact="true"]
 {