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It is currently not possible to determine whether a particular view/window/tab/TopComponent is shown or not, except from having to visually inspect every dockable corner of the screen area. I would suggest using a JCheckBoxMenuItem rather than JMenuItem in the Window menu. Being able to see the toggled state of what's shown and what's not in the huge list of possibilities (I'm counting 47 in my installation) would be a great usability gain. There's precedence to this in NetBeans, in the View menu where you can toggle the toolbar on/off etc.