116725 - CSS Z-index can not work when assign a negative value

Status: RESOLVED DUPLICATE of bug 78087

(Core :: CSS Parsing and Computation, defect)

Description

[Kevin Huang]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:0.9.7) Gecko/20011221
BuildID:    20011221106

img.x {z-index:-1}

when the z-index is assigned to +1, the display is right, the 
image displayed on the text.

When the z-index is assigned to a -1 (negative value), the image should be
displayed under the text. But in Mozilla 0.9.7, the image is not displayed. (IE6
displayed correctly).





Reproducible: Always
Steps to Reproduce:
1. Goto: http://www.w3schools.com/css/tryit.asp?filename=trycss_zindex2
2. You will found there are no image diaplyed.
3. In IE 6.0, go to the same URL, you will found the image is displayed under
the text.
4. Modify z-index to 1, you will found the image is displayed on the text both
in Mozilla 0.9.7 and IE 6

Actual Results:  There is no image displayed when z-index is set to -1

Expected Results:  When z-index is set to -1, the image should be displayed
under the text.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

This is a duplicate, but IIRC the problem is that -1 says to display it
underneath the body of the page.

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

*** This bug has been marked as a duplicate of 78087 ***