I have a theme which sets the background of my panel to a certain color, even when I tell it to be transparent via the panel properties. In the theme's gtkrc file, what do I need to change to set the background color to be trasparent? I haven't written my own themes before, so I'm kind of lost. Another theme I have does it right, but since I don't know how to read the theme file, I don't know where to start. 
What do I need to change to have a fully transparent panel?
gnome;theme
If I recall correctly, GNOME doesn't handle transparency correctly if the background is a pixmap. It is possible that the theme you are using uses a pixmap to fill the background, and as such it is not working as you expect.If this is the issue, the solution to such a problem would be to comment out any instances of bg_pixmap in your .gtkrc, and then restart the panel. ed or ex can do this for you like so:ed -s .gtkrc << EOFg/^bg_pixmap/s//#bg_pixmap/gwqEOFpkill '^gnome-panel'I'm not running GNOME, so I can't test this, but it should work.