With a combination of floats and form elements, clicking a <select> causes the layout to reflow incorrectly. (Annoying music on URL.)
Created attachment 20362 [details] Reduction testcase
This seems to be caused by the <br> no longer respecting clear:left when the <select> is clicked. Doesn't appear to happen if you replace the <br> with another element.
This is a regression since Safari 3.1 (only occurs in the nighly builds). Wow. A strange one.
Sounds like bug 18172.
Fixed with the commit of bug 18172, this was the same issue. Thanks! *** This bug has been marked as a duplicate of 18172 ***