<!-- Any copyright is dedicated to the Public Domain. http://creativecommons.org/publicdomain/zero/1.0/ --> <!-- This testcase has a -moz-box element with a block as its only child, which forms a containing block for an absolutely positioned grandchild. Also, in this case, the grandchild is taller than its parent and grandparent. --> <html> <head> <style> body { margin-top: 50px } .box { display: -moz-box } .relpos_parent { position: relative; width: 100px; height: 100px; background: lightblue; } .abspos_child { position: absolute; left: 30px; bottom: 10px; width: 20px; height: 130px; background: purple; } </style> </head> <body> <div class="box"> <div class="relpos_parent"> <div class="abspos_child"></div> </div> </div> </body> </html>