Would be great if you can enable Debug DbVisualizer in Tools->Debug Window and the Debug tab and then re-run the operation that causes the issue. Then use Help->Contact Support in DbVisualizer to send the log file to us.
That will also tell what database you are using.
I may be missing a setting or something, so if that's the case please let me know. If I use the data tab to view table data, I then make an attempt to delete a row. I then hit the save and reload button. The result is that nothing happens. The grid blinks and the screen refreshes and the row I had intended to delete is still there.
Of course, there is a good reason the row didn't go away: it is being pointed at through a foreign key from another table.
Question: Why doesn't DbVisualizer tell me it couldn't delete the row? Is there a way I can get it to notify me when it doesn't complete the requested operation because a database constraint was violated?