In-house tool used for maintaining large applications written in Clipper. Listen and be amazed, I am still getting calls from banks that need maintenance work on their production Clipper applications. There is a good chance that your trust might be tracked through a Clipper application.
CoEdit works equally well with Clipper, perl, and html -- any body of interrelated files. The new IDE for Java and C++ handle those realms very nicely. This I keep for some of the languages not supported by the new IDEs.
Written in late 1998. Not a lot that could be done to customize look and feel without completely rewriting the underlying library. Made a few non-Microsoft choices along the way to give it a little homer look.