Clicking on the database lookup button initiates a database lookup (after a confirming dialog). So far so good.
Clicking on the dropdown button next to it allows one to change the database for the next lookup. But it also initiates a lookup, which I don't find to be the expected behavior of such a control.
I suppose in some cases, a lookup fails, and the user wants to change databases and immediately search in another. This saves them a mouse-click.
But other aspects of MP3tag's operation lead me to always be sure all settings are correct before initiating something. So I change the database source when moving to a new folder where I may wish to use a particular source, even if I don't need to look anything up yet. The "automatic" lookup surprises me each time.
Perhaps this could be an option? "Initiate lookup after changing databases" yes/no, or something similar?
Exists in 2.37a and 2.37h
BTW there's no statusbar text for these buttons - "quick" lookup and standard lookup. There is for the "local freedb" lookup button, as well as all the others.