I've noticed this as well, and if you hurry it up you could lose some work. If anything 'goes wrong' and Ketarin closes on its own, or if Ketarin is canceled and it closes on its own, none of the changes made to apps during that session are saved.
It appears the database may be updated only when Ketarin closes down normally?
I've made many changes to apps -- new variables, scrapes, regex etc. -- then experienced a problem and Ketarin does not close down normally, all the changes I made during that session are lost.
So I've learned to close and re-launch Ketarin whenever I'd like to "commit" my changes. Would be nice if there was a save/commit button somewhere, so I didn't have to exit and start Ketarin back up. This could be especially helpful if the 'cancel' feature in Ketarin can be more 'immediate' than it currently is, as Ketarin might abort depending on what was in progress when it was canceled.
Just adding my $0.02 USD to your suggestion krislin :-)
--appyface