Raise event when click Close all but this

Sorry no, but it will raise the appropriate close events for any TabbedMdiWindow that is closed as a result of that operation.

Yes, but my TabbedMdiWindows take more time to get closed, because this I want to show a progreess dialog that says Closing..., but if I can't detect this behavior i can't make this, any idea?

Thanks!!

Your other option is to handle the DockManager.WindowContextMenu event, look through the DefaultContextMenu in the event args, and change the handler of the Close All But This item to your own handler. If you can't change the handler, then you could just remove that item and add your own item.