diff --git a/themes/base/jquery.ui.dialog.css b/themes/base/jquery.ui.dialog.css
index b49a4a76d..0e4f8edce 100644
--- a/themes/base/jquery.ui.dialog.css
+++ b/themes/base/jquery.ui.dialog.css
@@ -9,6 +9,7 @@
  * http://api.jqueryui.com/dialog/#theming
  */
 .ui-dialog {
+	overflow: hidden;
 	position: absolute;
 	top: 0;
 	left: 0;