In the combo editor,have a new place to select another combo, the undercombo.
So the combo editor would look like...
Edit Combo___________________[x]
Tile: 1200_____[ ] [ ] [ ]
Flip: 0
Cset 2:____Undercombo:____Next:
A. Frames: 0_____[ ]______ [ ]
A. Speed: 0
Type:
[None]
____[OK]_______________[Cancel]
This would make each individual combo be able to have their own "undercombo". Several ideas sprung up with this idea; for example, maybe the undercombo combo would only pop up if you selected a combo that required one (such as a bush/slash/slash->item/flower combo)
However! Any combo can be made pushable which requires an undercombo, so what if any combo could have its own selectable undercombo? If the combo has an undercombo but it never shows, then so be it, it will simply be "hidden," but if suddenly you place a push flag on the combo, then its undercombo will be shown once it is pushed!
This would be nice so you could have treasure chests, push blocks, and slashable combos all on the same screen!