232070 - Setting opacity using styleObj.MozOpacity=0.3 used to work in 1.5, now makes item invisible

Status: RESOLVED DUPLICATE of bug 228441

(Core Graveyard :: GFX: Mac, defect)

Description

[Zero Altitude]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.6) Gecko/20040113
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.6) Gecko/20040113

Up until 1.6, the above mentioned website used obj.MozOpacity = (small decimal)
to make certain animated slidy buttons less opaque (blend into the page).  Now,
setting MozOpacity to any value < 1 results in the items becoming completely
invisible (but still there: hover causes them to be made completely opaque
again, and this works fine on the site).  Other features of the site are that
the style is being set programmatically using JavaScript, and that the other
items on the page are absolutely positioned DIV elements, with non-zero
z-Indexes.  Test platform is OSX 10.3.2, Java 1.4.1.

Reproducible: Always

Steps to Reproduce:
1. Go to http://www.qualitycanwait.com
2. Observe the items sliding in from the top left
3. When they're done moving, they disappear

Actual Results:  
When the sliding UI elements are done moving, they disappear (when their
MozOpacity is set using JavaScript to 0.3, or any value < 1).

Expected Results:  
It should have done what Mozilla 1.5 did, and made these items not invisible,
but reduced their alpha blend or opacity to a percentage of their normal, full
opacity level.

Comment 1

[Christian :Biesinger (don't email me, ping me on IRC)]

I suspect this is more of a gfx problem than CSSOM...

Comment 2

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

*** This bug has been marked as a duplicate of 228441 ***