Of course, one thing lead to another and it's starting to look more like a word processor than anything else, but ... well, how about a stylesheet editor?
Sure, you can use the "Style" tab, and edit at will, but that's not exactly fun for everyone.
So, let's work on one. Here's the video of the current status:
Of course, this is about 1/20th of the stylesheet editor, but at least the dialog is there, and most of the remaining work is wiring dialogs, which is quick using designer.