User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:34.0) Gecko/20100101 Firefox/34.0 (Beta/Release) Build ID: 20140731030206 Steps to reproduce: Go to this example that use a lot of sticky elements http://jsbin.com/yulob/10/edit Scroll on X and Y axis, only the <header> is correctly sticky Actual results: thead, th:first-child & td:first-child doesn't have the expected behavior they should be sticky as well. Expected results: thead, th:first-child & td:first-child should be sticky as well according to the video attached. On Safari (8 but seems to be the same on v7) it seems fine. I got this result http://cl.ly/image/1H400a1S0f12/animated-2014-07-31_10h-58m-31s.gif (see attached video for better quality)