Size is wrong at session recall

A resized plugin will reopen at the default size (and it can be useful when the corner resize is outside the screen).

So two separate **problems**:
- recalling UI things at session opening
- sometimes the resizing corner is out of the screen bounds

No file, test, or entry point is named. Start by locating session-opening UI state recall and the corner-resize handling, then determine whether the two listed problems should be addressed separately. Done means resized plugin dimensions are restored on session opening and the resize corner remains usable within screen bounds.

Written by the indexing model from the issue text.