Created attachment 282326 [details] Test case to reproduce the issue An abspos element doesn't have a definite height unless it has a specified height or the top and bottom properties are not auto. For example, the following div doesn't have a definite height: <div style="position: absolute;"></div> However, this one will have a definite height: <div style="position: absolute; top: 0; bottom: 0;"></div> RenderBox::hasDefiniteLogicalHeight() is considering that both have a definite height which is wrong: http://trac.webkit.org/browser/trunk/Source/WebCore/rendering/RenderBox.cpp#L4760 This leads to wrong results in CSS Grid Layout check the attached example, the 50% in the 2nd row is resolved against the 100px of the first row when it should be considered "auto". You can check it live at: http://jsbin.com/xuyane/1/edit?html,css,output
Created attachment 282327 [details] Current output
Created attachment 282328 [details] Expected output
I am able to reproduce this issue in WebKit ToT (261811@main) using attached test case and also in Chrome Canary 113. Only Firefox Nightly 113 show expected output. Just wanted to share updated test results. Thanks!