Your comments

I confirm that the behavior is not very intuitive. Will try to include the fix into 1.5.6
I confirm the bug. Will be fixed asap.Thanks!
I confirm the bug. Will be fixed asap.
Thanks for the info! The "unknown tokenizer" error is not relevant - it appears because the DB is opened not from within CN.

Is there any chance you could send the crashing .db file to me? It would ease the debugging task enourmously! But of course you don't need to do that if you have any sensitive data in there.
Thanks for complimenting the icons)

Regarding the vertical arrangement, I have been advised  that it allows much easier comparison of the dates.

Could you please download SQLiteSpy from here, load your suspicious .db file into it, run the following command:
PRAGMA user_version;
and tell me what it returns? Thanks!