What is Terraria Map Editor a.k.a. TEdit?
TEdit is a stand alone, open source map editor for Terraria. It lets you edit maps just like (almost) paint! This thread is for feedback! It is an easy place to post issues and feature requests, so let me know if you have any.
MAKE A BACKUP OF YOUR WORLD BEFORE USING THIS!!!
It will make one for you (called *.wld.Tedit), but you should anyway.