For some reason codeeditor only seems to scroll one line at a time (1 in opera12 on arch, 1.5 in chrome on windows, didn't check others) instead of the usual 3-8 (unless you change you de/browser settings, but it should just honour that anyway).
This seriously limits the usefulness of scrolling in a lot of cases.
Version: unspecified
Severity: normal
The way ACE editor works makes that very hard to fix. It renders each line separately and does buffering on only a few lines before and after the visible parts (otherwise it wouldn't perform at all).
For me it scrolls quite smoothly on Mac OSX Safari/FF/Chrome
You might want experiment with settings in: http://ace.c9.io/build/kitchen-sink.html
See if you can find something that works better (animate scrolling ?)