here is a problem with TinyMCE editor when it is used from the phone and MyMobile theme is in use.

Steps to replicate:

1. Open the page that contain TinyMCE editor
2. Type something in
3. Move the cursor back in the middle of the sentence or the word and try typing again (the text will not be edited)
4. Try moving coursor back and forth, sometimes you will be able to use backspace but not other keys, sometimes it just ignores any input.

The issue only occurs in the MyMobile theme and only when it is used from mobile device (iPhone/iPad), if you switch to the different one (e.g. default 'no theme'), the editor input from mobile device will work fine. Also the issue does not occur in http://fiddle.tinymce.com/ (when the same 3.4.6 version is in use)