I also have a strong preference for the light UI and am happy that I can still set up my custom bars etc. and use it. I have XDP11 so I hope this option still works in version 12 of Xara's product line.

This is how you can do it:
  1. Customize your setup using the default dark interface. When you tick the relevant boxes in the Windows/Control bars dialog you can also have the large buttons.
  2. Once you're done, do not use the ctrl-shft-alt-S combo but close the program and go to where your Xara program is installed. So in my case the path is: "C:\Program Files\Xara\Xara Designer Pro X11" (if you’re using the 32-bit version you have to go the “Program Files (x86)” directory).
  3. Locate "xaradark_theme.xml." Make a copy of the file and save it in a different directory (this is only for safekeeping) and change the name of the file anyway you like (I added "OUT" to the file name -- again, this is only for safekeeping).
  4. Now start up the program again. It will show the light-gray, default interface.