boolean () { if (X11 == null) return false; List<ProjectFrameHelper> frames = WindowManagerEx.getInstanceEx().getProjectFrameHelpers(); // no frame to check the property so be optimistic here if (frames.isEmpty()) { return true; } IdeFrameImpl frame = frames.get(0).getFrame(); return hasWindowProperty(frame, X11.NET_WM_ALLOWED_ACTIONS, X11.NET_WM_ACTION_FULLSCREEN); }