Hi,
I created a patch that introduces a preference to show/hide the level/window widget of the main multiwidget editor.
This could be done through the API even until now, and you could also reduce the size of the widget interactively that had a similar effect. What I missed was that this setting was not preserved like e.g the perspective layout.
For compatibility, the widget is enabled by default.
Please, consider if this can be useful for you or others.
Best,
Miklos