Hello,
I use the great gmusicbrowser on my Netbook with installed Ubuntu Netbook Remix.
Unfortunately, it is not possible to maximize the gmusicbrowser window.
And the window is bigger as my display (1024x600). You are not able to decrease the window so that the whole window is displayed on the screen.
It would be nice if gmusicbrowser will better support small displays (1024x600) in future versions.
Have you tried different layouts?
I myself have made a layout to make better use of screen real-state (although admittedly it looks very weird):
http://forum.gmusicbrowser.org/index.php?topic=160.0
Try the Arkanoid theme.
The theme gives you a normal view and a reduced view (button top right, next to "Full Screen").
You can also resize all areas.
https://github.com/aboettger/gmusicbrowser/tree/development