title: Can't enter text from keyboard into a script editor window already containing code
body: <p>I'm using the latest script editor (rather than the legacy editor). No problem entering text from the keyboard into a newly created script file, but when I try to edit, say, Code.gs, already containing some code, the editor won't accept keyboard input (except Enter, Del) although it allows me to paste code from an external text file.</p>
  <p>If I clear (CTRL+X) all the code I can then type into the script window. But pasting the code back reactivates the lock. I'm guessing this may be something to do with the built-in code validation, but I cannot see how to disable this behaviour. I'm embarrassed to have to ask this question. TIA.</p>