bug#26323: 25.1; Closing frames (in fullscreen) under Mac OS cause immediate crash

[Matthew Bauer]

Hi Alan,

This is still an issue for me. Note that to reproduce you must have
"tabbing" enabled through macOS:

System Preferences -> Dock -> Prefer tabs when opening document -> Always

Any idea what is going on? It's still happening in my 26.0.91 build,
so I'm assuming it hasn't been fixed in master).