Textarea - editing while typing

I have a basic form with a single textarea field:

<form ng-submit='send(form)' name='form' novalidate=''>
      <textarea ng-model='message.content'  class='clean'  rows='20' placeholder="Type your message..."></textarea>
</form>

While typing (when the keyboard is visible) I can not edit what I have written by bringing the cursor to a random place within the text.

Is there any way to do that?

Thanks

Interesting enough, changing the ‘rows’ attribute to a lesser value fixes the problem???