Hello. I've found the solution on this site: https://groups.google.com/forum/#!topic/comp.soft-sys.matlab/vlwz1TouDYs
I think it is too late now but maybe I can help a few fellows.
Open your GUI in GUIDE. The "panel tab order" is exactly the order of the panel objects in the object browser window (View >> Object Browser).
As far as I know there is just one way to rearrange the order: Right click them and use "bring in front" and "send to back". Unfortunately, this throws them to the top most or bottom position, but it is possible to arrange them."
You need "SEND TO BACK" the panels in the inverse order you want to. You can then rearrange in the correct order. It worked for me.