There was a minor bug in the scissoring optimization that the root surface clear was happening before the scissor was actually computed. I went ahead cleaned up that code at the same time. No obvious regressions on layout tests on OSX, works fine with manual testing. Jonathan, can you please verify that this patch fixes the partial swap problem on your side before we flag it for official review? (Don't forget to manually remove the usingPartialSwap=false, otherwise it will seem to work without actually doing partial swap) Thanks in advance!
Created attachment 118128 [details] Patch
Fixes the problems that I was having with OSX 10.6
Comment on attachment 118128 [details] Patch OK
Comment on attachment 118128 [details] Patch Clearing flags on attachment: 118128 Committed r102294: <http://trac.webkit.org/changeset/102294>
All reviewed patches have been landed. Closing bug.