I'm not sure if this applies to all OSes or if it is just a Linux problem but when the DB is locked in KDE the task tray icon has a big red 'Don't do this' overlay on it. To me (and I'd guess 99% of everyone else) using the color red like this tells me that something is wrong or dangerous. In fact, having the DB lock after the specified interval is actually exactly what I want because it is safer. I suggest changing the overlay to a yellow lock style icon. Maybe just use the icon you use for on the 'Unlock Workspace' menu items would be good enough.