When performing a selection in the SQL Commander window, and then clicking out of the selection or trying to make a new selection, the original selection remains highlighted. No amount of clicking, tabbing, etc removes this selection highlight. The only workaround is hitting ESC after "deselecting" a selection.
This is after moving from 12.1.5 -> 12.1.7. Using dark theme, but tested with light theme and same behavior is experienced.
Only seems to affect SQL Commander window, data grid is not impacted.
This looks like a problem that has been reported by a few other users; we expect to have a fix for this in the next maintenance release.
You can check the availability by opening Help->Check for Update in DbVisualizer (and perform the upgrade when available).
Apologies for the inconvenience, thanks for taking the time to report this!
Regards / Peer