CodeMirror locks up in the notebook

[filmor]

Under certain circumstances that I'm not able to reliably reproduce (I'll try this now) when selecting code in a code-cell the browser locks up. This happens in both Firefox and Chrome on Windows and on Linux. Firefox is able to recognize the lock up and kill the CodeMirror script, which is looping in the function measureChar (line 958) in the code:

 for (var pos = ch;; pos += dir) {
      var r = data[pos];
      if (r) break;
      if (dir < 0 && pos == 0) dir = 1;
 }

[filmor]

This might be codemirror/codemirror5#1638.

[filmor]

Firefox says the blocking line is 963. You can reproduce this problem by wildly clicking around on your notebook's code cells. I'll see if the upstream patch fixes the problem.

[filmor]

I'm not able to reproduce the error with the given patch. Since it is included in version 3.15 of codemirror I suggest merging this release into ipython-components before the 1.0 release.

[minrk]

Thanks, last I checked CM 3.15 wasn't out. I will try to get it into 1.0.

[filmor]

This seems to have fixed the issue, thanks :)