I know this is just a proof of concept demo, but the "Code Pad" mode is built on CodeMirror and becomes unusably slow as soon as the document gets at all large

I know this is just a proof of concept demo, but the "Code Pad" mode is built on CodeMirror and becomes unusably slow as soon as the document gets at all large (few thousand lines) perhaps due to them not implemented a range of tricks for transforming CodeMirror's content efficiently, like the setValueNoJump extension here https://github.com/sagemathinc/smc/blob/master/src/smc-webapp/misc_page.coffee https://github.com/sagemathinc/smc/blob/master/src/smc-webap... DISCLAIMER: I've spent way too much time on synchronized CodeMirror editing...