Unfortunately, we don’t have that capability built in at the moment, since it’s a relatively rare operation, but since all of the cabinets drawn by CabWriter are regular SketchUp components, you can use standard SketchUp tools to modify the stile and panel in question. I do this once in awhile myself when there’s something a bit out of the ordinary. You can use the Push/Pull tool to make the stiles longer, then use the move tool to move the bottom rail down, and finally pull the panel down to fit. If you want to make sure that CabWriter doesn’t interfere with your changes if you edit the cabinet, you can open the Extended Entity Info window, select the components you modified or moved, and check the “CabWriter Protected” box at the bottom. Then, whenever you edit the cabinet, CabWriter will not overwrite your changes.
Glad you’re getting some time on the software, let us know if you have other questions or need more help with this problem.