Incorrect layout when specifying both corners with fixed positioning

Hello,

my name is Thomas Grundmann and I guess I have found a bug with fixed 
positioning. Assuming the following file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
 <head>
   <title>Test fixed possioning</title>
 </head>
 <body>
   <div>hello</div>
   <div style="
     position:fixed;
     top:0;
     bottom:0;
     left:0;
     right:0;
     background-color:red;">world</div>
 </body>
</html>

Using this file the result should be a red colored div having 'world' as 
content that covers the whole content pane (picture1, right side; made with 
firefox) but the result is different (picture1, left side; made with FS 
browser demo). It seems that if the left property has a different value 
than 'auto' the right properties is ignored (handled as set to 'auto'). So 
this behavior equals to the one for relative positioning. As far as I 
understood the css2.1 specification this is wrong.

It is interesting, that this does not appear with absolute positioning.

For the FS screenshot I used the browser demo with the xhtml file as input 
(modified the form.xhtml file).

regards
Thomas Grundmann

Original issue reported on code.google.com by Peter.Br...@gmail.com on 29 Apr 2010 at 2:02

Attachments:

picture1.jpg

MaikJaek / flying-saucer

Incorrect layout when specifying both corners with fixed positioning #268