There are no events when a window's attributes change, whether by the app or by the system: title, resizable / minimizable / maximizable / closable, always-on-top, and so on. A generic custom title bar can't update its buttons when some other part of the app calls setClosable(false).
Proposal: a WindowAttributesChangedEvent (or a few specific ones), emitted by the setters and, where the platform reports it, by external changes (for example WM_SETTEXT, KVO on NSWindow.title).
Background:
There are no events when a window's attributes change, whether by the app or by the system: title, resizable / minimizable / maximizable / closable, always-on-top, and so on. A generic custom title bar can't update its buttons when some other part of the app calls
setClosable(false).Proposal: a
WindowAttributesChangedEvent(or a few specific ones), emitted by the setters and, where the platform reports it, by external changes (for exampleWM_SETTEXT, KVO onNSWindow.title).Background: