Debug mysterious window resize?

I am unfortunately faced with a large legacy code base in which Storyboards are heavily used. Now, for some reason, the entire app window is resized if a certain View Controller becomes visible.

The issue: Apparently, there aren't any conflicting layout constraints (no LAYOUT_CONSTRAINTS_NOT_SATISFIABLE errors are raised on display of the view controller).

There are also no calls to setFrame on the corresponding window.

So, how do I debug this? Capturing the view hierarchy didn't provide any helpful insights, and ideally I could just force the window to not resize (due to possible constraint errors).

Is there any way to achieve something like this? If not, how can I go about debugging this?

Any help on this would be greatly appreciated.

Debug mysterious window resize?
 
 
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