Feel free to leave comments and suggestions for Ace Editor.
All I can say is that I like it; there was a minor issue with the default skin and the developer of Ace was very responsive and got it fixed quickly.
A serious show-stopper in version 1.3.2!
When inserting a MODx tag, upon the first [ Ace immediately adds the closing ] for you, thus resulting in [ or if you're quick in typing the [[, 
Danya, can you compare Ace to CKEditor? I believe you worked on that one as well. Would we want both - as in one for code and one for markup? I see them both as being code.
Loved ModX when I was using it a few years ago. Shifted to WordPress, sorry. Thanks, all.
Ace is a syntax highlighter and code editor, it is by no means a WYSIWYG editor. You can specify it (or CodeMirror) as your resource content editor if you want to, but I use both.
Is there a fullscreen-mode for ace? (in Codemirror you can toggle it with F6, it's quite useful in long files)
Yes, you can toggle ace with Ctrl+F11
That was AjaxManager. You should read installation instructions for AjaxManager.
I guess there is still Ace plugin, wich tries to load ace class. Delete plugin manually.