Synchronously and immediately updates the list of Window on this .
This bypasses the standard update mechanism, where the list of Window is updated in the idle loop.
This is usually a bad idea for both performance and correctness reasons (to get things right, you need to write model-view code that tracks changes, not get a static list of open windows). However, this function can be useful for small applications that just do something and then exit.
| this |
a Screen. |