Thanks, Violet, for the speedy response! Opened your editor up for a bit - looks great! There's no help file for it (as you mentioned yourself on the download page) - once I get more versed in it, you want me to help you write one?

Edit:
On my Windows 8 installation, though (the only Windows installation I have that supports a 64 bit program like MLLE), it's somewhat buggy. It doesn't open Haunted or the NewHaunt tileset, claiming either incompatibility with 1.23 or, when switched over to version 1.24+, it makes all screens in the editor white and unusable until I switch to a new tileset. There's also a lot of unhandled exceptions being thrown in my face, but I can choose to ignore them and at least the program doesn't crash.

Having fun creating my first level in years, though! Now, to pray I never run into that deadly Stack Overflow error that kills all level progress...

EDIT II:
One point of serious critique I have, though, is that there seems to be no animation editor present. That's quite necessary in a JCS editor in my view. Hope you read this.