I really miss is the possibility to specify the background for a scope - not a symbol's background but the background of the whole editor, when editing a file belonging to a certain scope.
Colors & fonts | General | Default text | Background is used for all files I edit. Instead it would be cool to specify it for each scope (my wish - for each module, actually). That would make life so much easier... e.g. to distinguish server modules of the project from client, j2se form j2me, etc...just by side-vision..