Vandala,
Some advice / constructive criticism from someone who earns his keep as a programmer / analyst...
When going from start to finish, you're going to have to load all the mod files into some sort of memory structures and then bind them to your UI. I think you should, before coding any UI, figure out what method you will use to store the mod data in memory and what sort of UI would best bind to that method. Something I know you'll use, but I saw not a one of in your screenshots, are grid views (I don't know what they're called in your toolkit).
Your form is entirely too large, with too many things crammed on it. I'm assuming the main object on your form is some sort of tab control widget. What you're most likely going to want to do is, within each of those tabs, add another tab control widget with the tabs at the top. So, for your DF: Game Setting tab you could have within it a tab for d_init, a tab for init.txt, and a tab for color.txt. Actually I'd suggest splitting the d_init and init.txt into more than one tab each, because they'd still be pretty big.
Something else I just noticed, you don't have any check-boxes. Typically Y/N items like temperature, weather, etc would be check-boxes not buttons. If you're not going to use check-boxes I'm wondering how you'll indicate whether those items are enabled or disabled.
Stuff will be stored in .txt files if that's what your asking, otherwise I don't understand the question.
Also don't know what a grid view is. (don't recall spotting such a thing just yet.)
You probably don't have to worry to much, as I said I'v got a friend who knows this stuff, he works as a programmer himself, he'll know what's what when I get to that stage.
The buttons themselves are on/off switches, this takes less programming work.
I'll certainly keep the tabs in tabs idea in the back of my mind while I work.
Thank you, advice / constructive criticism is always appreciated.