Build r157388 has a launch error that prevents it form starting on 10.8.5. Returning to r157368 solves the problem. Also there is a rendering bug that popped-up some 10 nighties ago. I usually have about 3 windows open with some 10 tabs each. If I try to select text in one of the tabs (a medium heavy page), than portions of the surrounding text including the one I'm selecting disappear. If the selection is continued than the text highlights, but upon releasing of the selection text disappears again. A reload fixes the problem.
*** This bug has been marked as a duplicate of bug 122736 ***