If you call setWantsKeyboardFocus(false) on a document window then when it becomes active window the title bar buttons (close, minimize..) are disabled.
You can reproduce this behaviour in the Plugin Host Demo by setting setWantsKeyboardFocus(false) in the PluginWindow constructor. If you do it before the "setVisible(true)" on line 51, then the buttons are disabled when the plugin window first opens. If you do it after the setVisible(true) then the buttons will be enabled at first, but once you switch focus back to the main window and back to the plugin window the buttons will be disabled.
This is tested on OSX Mavericks (10.9) with the latest tip.
What I'm trying to do is allow my audio host app receive key events when a plugin window is active. setWantsKeyboardFocus(false) appears to do the trick as I expected it should, it just breaks the buttons.. If the bug is not easily fixable then any suggestions for accomplishing the same thing properly are appreciated. Thanks!