I cannot verify the problems you've described, but testing around a bit I discovered a problem with the auto-snap-in method in a two-screen environment.
It is fairly tricky to position a window on screen-2 when the panel window is wide opened.
It is impossible to dock on screen-2 edges.
It just happens that the title line of the panel window is out of sight on screen-2. I don't know how to drag it back ... Any suggestion?
Unfortunately there is no [Alt--] keyboard command available.
DD.20080403.1454.CEST
By tricky resizing the right and left panel window edges I have the panel window back on screen-1, but I cannot get to the title bar to drag the window anywhere else on the screen, e. g. to dock it on the left edge. How can I get the panel window to normal state?
DD.20080403.1512.CEST
I got it! Dragging the tag panel's lower edge up to the top of the screen making the panel window rather small and afterwards resizing it a bit into down direction results in having an auto-snap-in frame that enables me to dock the tag panel window back to the left edge of the screen.
Hmm, I think, Mp3tag should have a new one-click-feature: "Collect my panel windows into my app view".
DD.20080403.1538.CEST