Do you get an error message? Can you maybe give me an account for your FTP server so I can try to reproduce it here?

Fixed problem for the next version.

Ok, I could reproduce this in the shipping version of Textastic 2.0.

It seems like I already fixed this in the development version of Textastic 2.1 when I fixed the bug at http://feedback.textasticapp.com/feedback/15340-wrong-behaviourcrash-when-entering-accented-characters-using-a-hardware-keyboard/

This was an error that was rather similar to your problem because it also happend when deleting marked text – or as you wrote: not determinate strings.

Thank you, that would be great!

Thank you for reporting this.

It would be really helpful if you could tell me exactly which keys to press on the keyboard to make it crash since unfortunately I don't know how to read Hiragana or Kanji characters.

Did the problem occur with the virtual on-screen keyboard or a hardware keyboard?

What would probably help the most would be a small video demonstrating the problem.

Thank you, but I think I found a great solution for a future version of Textastic. I've updated the feedback accordingly.

I'm working on a solution. See here: http://feedback.textasticapp.com/feedback/8111-better-syntax-highlighter/

I just found out that this only happens with the onscreen keyboard and not in all cases. With a hardware keyboard you can tap on the "x" and also use escape to decline the auto correction suggestion.

I will investigate further...

Good idea. Should this be an options in the global settings? I'm just not sure where this option should go.