I've got the time to work more on this http://bugzilla.gnome.org/show_bug.cgi?id=130123 (actions to change to next/prev palette color)

but am not sure what I should do. It works fine, pragmatically, and is clean. The current implementation uses the colormap editor if it's available and the image has a colormap,
and the palette editor otherwise, on the principle that you mainly want to use colors from the colormap when editing an indexed image.

Mitch pointed out that these (colormap and palette) should be separated, however that breaks their usefulness: having to assign different keys to two virtually identical sets of actions is un-mnemonic and eats up keys (and in my experience, you will only want to access one of (colormap|palette) at a time)
What would be good is if actions could signal failure and be chained up -- So that if the 'next color in colormap' action failed, the 'next color in paletteeditor' action would run (assuming they can be both assigned the same key.). Perhaps I should mention that to the GTK+ developers.

I'm trying to figure out what to do next. Is this patch acceptable in its current form? If not, what would be a clear improvement over its present
implementation?