Appears to be broken in Flutter 3.22.0

[HankG]

I've created a bug over on the Flutter board related to this: flutter/flutter#148653

The TL;DR is that it appears that something in commit 8e418d18185697e56024ef3d5784afba4ac96370 seems to have broken something that is being done with rendering the popup on Linux. I haven't had luck figuring out what exactly yet though. I'm going to keep dabbling with it to see if there is a work around. For now, using the standard example, in previous releases one would get:

...but now one gets:

The case degenerates in a different way in my own app though.

[HankG]

This change probably fixes it, since this was the test case I reported as being broken. flutter/flutter#148653