Index: applets/taskmanager/package/contents/ui/ContextMenu.qml
===================================================================
--- applets/taskmanager/package/contents/ui/ContextMenu.qml
+++ applets/taskmanager/package/contents/ui/ContextMenu.qml
@@ -574,7 +574,8 @@
                 checked: menu.visualParent && menu.get(atm.IsGroupable) === true
 
                 text: i18n("Allow this program to be grouped")
-
+                icon: "view-group"
+                
                 onClicked: tasksModel.requestToggleGrouping(menu.modelIndex)
             }