New Folder dialog issues Wicket Warning

This doesn't seem to affect functionality.

To reproduce (from the smoketest in Go Green, but also occurs in at least testsuite):

• On the dashboard click on "to the documents"
• Click in tree view on triangle before "Hippo Ga Groen" (i.e. the DUTCH version)
• Click in subtree on label "Evenementen"
• Access context menu of "Evenementen"
• Click on "Add new event folder..."
• Type "2006" into name input box
• Click on "Edit" radio link
• Type "twothousandsix" over existing text "2006" in URL name text box
• Use "enter" key to confirm dialog

The complete warning in the cms log is:
2012-08-29 09:25:54,603 WARN [http-8080-7] [org.apache.wicket.request.target.component.listener.BehaviorRequestTarget.processEvents():146] component not enabled or visible; ignoring call. Component: [MarkupContainer [Component id = button]]