Your comments

I thought about tabs but they take away a lot of screen real estate.

Having a list of recent files might be a solution. I'll consider it for a future version.
I also had this problem when I enabled snippet sharing in TextExpander while in the "Notes" mode. Try to switch to "Snippets" in TextExpander and then enable "Share Snippets" in Settings. I think this is a bug in TextExpander.

You can switch modes by tapping on the "te" balloon icon in the TextExpander toolbar.

Please let me know if it worked.

Thanks for mentioning the type. This is fixed for the next version.
You can already rename a file: open the file, then go to the file properties popover and tap on the file name.
Well, it currently looks like this in Info.plist:

<key>UIAppFonts</key>
<array>
<string>DejaVuSansMono.ttf</string>
<string>luximr.ttf</string>
<string>monof55.ttf</string>
</array>

If I don't register the font files here, they are not available in the app.

You can look up UIAppFonts in the docs.