Freeciv

3.1.4
to repro -
1 edit file share/freeciv/trident/tiles.spec by commenting out the "user.infratile"
2 start freeciv-qt
3 click on options, go to Graphics tab
4 choose Tileset (Square) -> trident
5 click Apply, app exits without showing any dialog

If instead, edit file share/freeciv/amplio2/terrain1.spec again
commenting out the "user.infratile", then when you start freeciv-qt
you immediately get the "Tileset error" dialog before the app exits.
The difference is in the first example the code path calls ask->show(),
and in the 2nd example it calls ask->exec().

gtk clients work OK for both cases.