When a Glass window is minimized, maximized or restored to the normal state, Glass generates corresponding WindowEvent: MINIMIZE, MAXIMIZE and RESTORE. The event is dispatched from the native level to Java via Window.notifyResize() method. However, this method handles these 3 event types internally, the only event type forwarded further is RESIZE.

At the Quantum level, these events are synthesized. Here is an example:

        if (platformWindow.minimize(iconified) == iconified) {
            if (stageListener != null) {
                stageListener.changedIconified(iconified);
            }
        }

Instead, stageListener.changedIconified() should be called from GlassWindowEventHandler.