diff --git a/bundles/org.eclipse.orion.client.editor/web/orion/editor/contentAssist.js b/bundles/org.eclipse.orion.client.editor/web/orion/editor/contentAssist.js
index <HASH>..<HASH> 100644
--- a/bundles/org.eclipse.orion.client.editor/web/orion/editor/contentAssist.js
+++ b/bundles/org.eclipse.orion.client.editor/web/orion/editor/contentAssist.js
@@ -409,7 +409,9 @@ define("orion/editor/contentAssist", ['i18n!orion/editor/nls/messages', 'orion/k
 				self.position();

 			}

 		};

-		document.addEventListener("scroll", this.scrollListener);

+		if (document.addEventListener) {

+			document.addEventListener("scroll", this.scrollListener);

+		}

 	}

 	ContentAssistWidget.prototype = /** @lends orion.editor.ContentAssistWidget.prototype */ {

 		/** @private */
addEventListener is not available on IE8