java.lang.ClassCastException
	at org.netbeans.core.windows.util.WindowUtils.dockIntoNewMode(WindowUtils.java:244)
	at org.netbeans.core.windows.util.WindowUtils.dockIntoNewMode(WindowUtils.java:203)
	at org.netbeans.core.windows.frames.DefaultContainerImpl.doPerformAction(DefaultContainerImpl.java:771)
	at org.netbeans.core.windows.frames.DefaultContainerImpl.access$000(DefaultContainerImpl.java:91)
[catch] at org.netbeans.core.windows.frames.DefaultContainerImpl$1.run(DefaultContainerImpl.java:758)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:448)
	at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:197)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:144)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)