numeric
An X-windows handle. Passing this value to an external process permits the process to access graphics within the window’s display area. The handle in fact points to a Window in the X server. The value of this element cannot be changed.
For display windows, all maintenance of the X window must be done by the external process, including managing expose and resize events.
This element has no other use within the modeling language and cannot be changed by the user. In fact, the system never writes anything to the canvas. This is entirely up to the external process.