After the search field had sat in the unfolded sidebar's toolbar,
folding the Duo could leave the list with no search at all. UIKit kept
the search controller's toolbar placement instead of moving it back to
the navigation bar.

Folded, the workspace search refuses toolbar integration, which is also
right there because the tab bar owns the bottom of the vertical bar.
That makes UIKit re-place a visible search in the navigation bar. A
search whose column a detail covers during the change is not re-placed,
so it gets a new controller instead, which UIKit places when Back
reveals the list.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>