Fix an occasional problem with the new CodeMirror optimizations.
Review Request #6439 — Created Oct. 14, 2014 and submitted — Latest diff uploaded
We were throttling how often the 'change' event handler for CodeMirror
was getting invoked. However, this meant that there was a window of time
where CodeMirror could be closed/destroyed before the 'change' event
handler was called.We now check for this and bail if CodeMirror is no longer with us.
Could no longer reproduce the problem.
Still saw change events firing.