<!DOCTYPE html> <html> <head> <title>Testcase Bug 851514</title> <style> #parent { position: fixed; height: 30px; width: 30px; background: green; left: 70px; top: 70px; } #child { position: fixed; top: auto; left: auto; width: 10px; height: 10px; background: purple; } </style> </head> <body> <div id="parent"> <div id="child"></div> </div> The purple block should be inside the green block. </body> </html>