I'm glad to inform that 0.2-dev branch is frozen. This means that it is a time to stop adding new features and start testing. Of course, I use JuffEd myself (actually, it was written using itself since version 0.1 :)) but it becomes bigger and I can miss some bugs (especially if I don't use any feature). Well, bug tracker is open and you are always welcome to report a bug. And you are more welcome to make a feature request.
Further development concerns using QScintilla editor component which provides several very useful things like code folding, "smart" auto-indent, syntax highlighting for huge amount of languages and so on. Also I'm working on plugins mechanism.