I don't think there is a way to re-size a display panel.
I use stretchers if I think I will need to re-size. You can add the stretcher and turn it into a phantom part until you need it.
All of the face frame top and bottom rails on this cabinet are stretchers so that they will re-size with the cabinet. The front and back top, the deck, the back and the nailers are also stretchers because the cabinet is 114" long and I had to split them.
It will be easier for me to show you one of my library cabinets.
These cabinets resize great in width and depth. If you re-size height you need to change some settings in the stretcher editor after the re-size.
The addition of formulas to the stretcher editor would fix this.
The other problem with these cabinets is all of the face-frame parts added in the stretcher editor must be sheet stock. I have to manually add them to our face frame cut lists. It would be great if we could use board stock as well as sheet stock in the stretcher editor.
Even with these problems, these cabinets still save a lot of time.