diff --git a/modules/ve/ui/styles/ve.ui.Widget.css b/modules/ve/ui/styles/ve.ui.Widget.css
index 75e787d929..9405f06ddd 100644
--- a/modules/ve/ui/styles/ve.ui.Widget.css
+++ b/modules/ve/ui/styles/ve.ui.Widget.css
@@ -385,7 +385,7 @@
 	outline: none;
 }
 
-/* ve.ui.CategoryListWidget */
+/* ve.ui.MWCategoryWidget */
 
 .ve-ui-mwCategoryListWidget {
 	border: 1px solid #CCC;
@@ -393,11 +393,22 @@
 	padding: .75em;
 }
 
+.ve-ui-mwCategoryListWidget-items {
+	/* MDN claims we need to use word-wrap: break-word; and that it's been renamed to
+	 * overflow-wrap: break-word; , but the only thing that actually works in practice is
+	 * word-break: break-word; (which is not documented in any standard at all). So we just use
+	 * all three.
+	 */
+	word-break: break-word;
+	word-wrap: break-word;
+	overflow-wrap: break-word;
+}
+
 .ve-ui-mwCategoryInputWidget {
 	float: left;
 }
 
-/* ve.ui.CategoryListItemWidget */
+/* ve.ui.MWCategoryListItemWidget */
 
 .ve-ui-mwCategoryListItemWidget {
 	position: relative;
diff --git a/modules/ve/ui/widgets/ve.ui.MWCategoryWidget.js b/modules/ve/ui/widgets/ve.ui.MWCategoryWidget.js
index b83ca6dee2..43a930e7d2 100644
--- a/modules/ve/ui/widgets/ve.ui.MWCategoryWidget.js
+++ b/modules/ve/ui/widgets/ve.ui.MWCategoryWidget.js
@@ -49,7 +49,7 @@ ve.ui.MWCategoryWidget = function VeUiMWCategoryWidget( config ) {
 	// Initialization
 	this.$.addClass( 've-ui-mwCategoryListWidget' )
 		.append(
-			this.$group,
+			this.$group.addClass( 've-ui-mwCategoryListWidget-items' ),
 			this.input.$,
 			this.$$( '<div>' ).css( 'clear', 'both' )
 		);
@@ -59,6 +59,8 @@ ve.ui.MWCategoryWidget = function VeUiMWCategoryWidget( config ) {
 
 ve.inheritClass( ve.ui.MWCategoryWidget, ve.ui.Widget );
 
+ve.mixinClass( ve.ui.MWCategoryWidget, ve.ui.GroupElement );
+
 /* Events */
 
 /**