You think that renaming files is a kinda obvious function for a decent IDE. Well, Chpokk (my .Net IDE project) finally can do it. I'd say it wasn't as easy to implement as it seems, but here you are. Didn't do it until now just because nobody asked for it.
Speaking of which, if you need a feature or two, just ask for it using the Feedback tab, and you'll get the best IDE in the world -- the one that has every feature that you need.
Back to renaming, just double click an item, type in the new name, and hit Enter or click away. Just like in any other file explorer. If it doesn't work for you, or you have an idea on how to improve it, please contact me, and I'll fix it for you.