App Warning dialog does not show up if project was created by different app

[backface]

The warning (inform dialog) on loading a project that was created by a different app does not show up (For instance TurtleStich vs Snap). As far as I see, for now, the if condition/app check actually works, but the inform dialog (silently) does not show up:

fixe in upstream. see: https://github.com/jmoenig/Snap/issues/3191