I tried looking specifically at the "Confirm on exit" option and it does have an impact on slicer behavior - it corresponds to the "Do not show this dialog anymore." checkbox in the exit confirm dialog. It seems to work correctly and is preserved across launches.

However, the state of the checkbox is not correct at startup, which seems to be a KWWidgets bug.

If the checkbox status is not correct on startup, I am not sure how the actual status of a setting can be known?

I tried with splashscreen, and with Slicer settings->confirm on delete, and they don't seem to have any effect on slicer behavior.

Maybe these checkboxes should not be there at all if they are not initialized correctly/don't have effect.

I agree the initial state of the checkbox is a bug - (kwwidgets bug).

But you should be able to confirm that the confirm on delete behavior is modified by changing the checkbox - just try starting and exiting a few times when you have modified the state.

I agree "confirm on exit" works. But the other features ("confirm delete", "splash screen") are not. I didn't check all of them, so I don't know which other ones don't work.

Closing. Slicer3 is not being developed anymore.