Help on Altering a specific feature of a UI
 

Ok,
The other day i downloaded and installed the fetish nightfall ui. I love it, and think its great, before it i had a ui which was quite good, but i prefer a couple of windows in the old ui to the equivalent new ones.
What i wanted to know is how do I replace some of the current windows with some of the old windows i had. Do i just replace the correct file? If so, how do i know which file alters which window.
Tnx for any help.

DO NOT copy the files from the Default folder to replace them. If you do that, you won't get updates made to the default windows, and things will break down the line.

Simply delete the file for the window you want restored to default, and it will use the default window automatically.