diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index 21702afaf..daa88f029 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -1599,7 +1599,8 @@ var ZoteroPane = new function()
 	 */
 	this.updateItemPaneButtons = function (selectedItems) {
 		if (!selectedItems.length) {
-			document.querySelectorAll('.zotero-item-pane-top-buttons').forEach(x => x.hidden = true);
+			// TODO: Remove Array.from after Firefox 45 support is removed
+			Array.from(document.querySelectorAll('.zotero-item-pane-top-buttons')).forEach(x => x.hidden = true);
 			return;
 		}