Your comments

I'll try this the next time it happens, but quitting the app and re-opening it solves the problem for a short time anyway so it will be difficult to tell initially if it worked. Also, I believe I opened the file using an Alfred workflow, but that's how I've been opening all of the files so I don't know why it would be that.

It just happened to me again, so I checked the file encoding which is Unicode (UTF-8) with Unix line endings.

The console shows this error: 

4/26/13 10:28:48.616 PM sandboxd[1851]: ([804]) Textastic(804) deny file-read-data /path/to/file/fileName.js

The full log report for the error is here:

I would really like code folding to be implemented. It would be especially nice if it remembered what pieces were folded when re-opening a file.

Good to know. I'm using the app as we speak and I like it. Looking forward to your updates!

This is the one thing that would keep me from using this on a regular basis for all my coding. Is your order of development based on how many votes a feature gets? Or are there certain features *ehem..this one* that you're going to be pushing to the top? Thanks! :)