@ Sergoicornaga: Let me show you what I've got, so you can see why I need to make changes. (See attachment.) The green area is where the 3rd-Part-Tools style interface will be. That and the text editor are too small. Also, there are empty spots in the map pane caused by the addition of the preview strips.
@ Raicuparta: That's a great idea about the color switching. My greatest displeasure with the mock-up is it's so cluttered.
eta: Please ignore my "Classic Windows" theme.
Edit: Added another mock-up. This one keeps things closer to their original positions. Clicking "test" would replace the sound selectors with power and flag choices.
Edit: 18Mar2012: It's a little know fact that Knytt Stories allows gradients to be any width. However, the level editor shows an error message if the gradient isn't 24px, 120px, or 600px wide. My editor allows any factor of 600 now. For example, you could use a gradients that are 300px, 200px, or 60px wide.
In other news, the ini editor grabs focus when it's clicked on. I know it seems pretty basic, but the text editor object wasn't set up for it, so I had to be really creative.
I still haven't decided on a layout for the map editor yet. I'd go with the version attached here, EditorLayoutD.png, if it weren't for the mini-map being so small.
Edit: Deleted pictures. See newer version below.