Following on from what Braxt said, all you would have to do is create one panel for 1600x1200/1024x768 (depening on you screen resolution setups in your game), then create a new function to chnage the panel size when the resolution is lowered, then call it in the main resolution change function, and on F5 it should change - I have not tried it myself but it should work - I'll try and make an example of what I mean (I probably am making no sense as I need sleep - well, better get some )

Cya!