Another thing I would like to add, Many times, you don't even need two menus (selection, list). For example, map generation can come just in the bottom one, same with Terrain placement, same with Units too infact. As such everything can be incorporated into one set of box, but two might be useful for triggers and camera sequences. So I would suggest keeping one of the box relative to the menu selected, you don't need it all the times, unless you plan to have a way to incorporate all functions in two lists.