On trunk revision 13949, I've added a single line to DbState to enable a signal for the Media View. It is called "media-changed". If no one objects to this change (and name), I'd like to add the following signals to DbState:
What do these allow? If you throw the signal on a row change (also added to 13949 to mediaview) then you can have gramplets and other tools that respond to the active row in a view. You can see an example of this with the beginnings of Rob's Exif image metadata editor from gramps-addons.