I often use the accesskey "," (comma) to put the cursor in the editing window when editing. However, this doesn't work when syntax highlighting is toggled on.

Steps to reproduce

1. Make sure that the accesskey works normally by toggling syntax highlighting off, clicking anywhere outside of the editing area and then pressing Alt+, (it could be Alt+, Ctrl+Alt+,, Ctrl+Shift+, or something else depending on your browser/setup/OS)
2. Toggle syntax highlighting on
3. Press outside the editing area
4. Press Alt+, – it won't put the cursor in the editing area.

Fix

Luckily, the fix, which I've tried in my browsers' inspect mode, is extremely easy: Simply add accesskey="," to the div that has contenteditable="true" (i.e. <div class="CodeMirror-code noime">).