Remember last control state per user

The last update lets me bind the set property to the newly exposed Collapsed-Property.
Getting and setting works fine. But the rendering produces similar results as the panel-issues which were fixed in the last release also ( Collapsed Panel seems to block elements below it )
Expanding and collapsing the panel by hand lets everything look normal again.

Here's an example:
panelBug.zip (2.0 KB)