On faster machines we can highlight faster, while on slower machines text editor is a bit unresponsive while highlighting the text. We can implement a simple heuristic to work smoothly on both cases.
Created attachment 88626 [details] Patch
Comment on attachment 88626 [details] Patch Clearing flags on attachment: 88626 Committed r83276: <http://trac.webkit.org/changeset/83276>
All reviewed patches have been landed. Closing bug.