348637 - layered components "bleed through" when "allow pages to choose own colors" is unchecked or in high contrast mode

Status: RESOLVED DUPLICATE of bug 255411

(Core :: CSS Parsing and Computation, defect)

Description

[Becky Gibson]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6

When elements are layered over one another, the background color becomes transparent when the operating system is put into high contrast mode.  
Set your Windows OS to high contrast mode and load the google suggests url.  When you start typing and the drop down occurs, the background is still visible below the drop down.  The background of the drop down should be solid and not bleed through.  

Reproducible: Always

Steps to Reproduce:
1.Set Windows OS to high contrast mode 
2.start FF and load http://www.google.com/webhp?complete=1&hl=en
3. when you type drop down of suggestions appears - note that the background of the drop down is not solid and the elements beneath it are visible.

Actual Results:  
elements underneath the drop down are visible

Expected Results:  
The background of the drop down should be solid.  

IE had this problem in early releases of IE 6. They released a patch and it has been fixed in IE 6 updates.

Comment 1

[Aaron Leventhal]

When you set high contast on in Windows, we automatically act as if the pref "allow pages to choose their own colors, instead of my selections above" is unchecked.

Is this bug dependent on high contrast or just that pref in general?

Comment 2

[Becky Gibson]

The bleed through will also occur in "normal" display (with NO high contrast mode set).  Just uncheck the checkbox "allow pages to choose own colors instead of my selections above" on the Tools Options General Colors panel.  Issue can be seen at the same google suggests URL.

updated the severity to major because this makes development of accessible drop down menus impossible

Comment 3

[Aaron Leventhal]

This should block 1.9 at least.

Comment 4

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

To fix this we'd need to completely change the way we implement that pref, so that we essentially convert all non-transparent backgrounds into the default background color, but leave any backgrounds that are transparent as transparent.

(Although we might be able to do some fun CSS extension that would allow us to express that in CSS.)

Comment 5

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

I think this is a duplicate, though.

Comment 6

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

Hrm, I couldn't find the bug I remembered, although bug 58048 and bug 255829 are other bugs on this feature.

Comment 7

[cq142857]

Another good example of this problem is amazon.com: mouse over "See All Product Categories".

Possible duplicates include 348957 322664 370485.

Comment 11

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

(I'll attach the more accurate fix I was planning to bug 58048.)

Comment 12

[grace]

The problem got fixed by unchecking "always use my colors" box. The problem doesn't occur with the default colors.