12065 - Fixed elements without background display ghosts of other screen sections

Status: VERIFIED DUPLICATE of bug 4209

(Core Graveyard :: GFX, defect, P3)

Description

[BVoigt]

Observed on:
Windows NT4 SP5 (didn't check any others)
Mozilla apprunner builds 19990727, 19990728, 19990729, 19990817 (didn't check
any others)
Does not occur in viewer: defaults to black background

When a DIV using fixed positioning does not specify a background, the previous
contents of the device context are used as the background.  This is probably
less a bug in the renderer itself than a failure to provide a appropriate
default background.  I would expect the page-background color to be used,
although any solid color would be usable.

The following code causes the Mozilla toolbar to be displayed within the fixed
DIV:
<div style="position: fixed; left: 0; top: 0; width: 50%; height: 400px;
overflow: auto">
</div>

EXAMPLES (Please note that these files are on my personal computer and may not
be available at all times)

http://ksu.kas.com/nsbug1.htm (screenshot http://ksu.kas.com/nsbug1.gif)
     Simplest possible case: DIV in document by itself.

http://ksu.kas.com/nsbug1b.htm
     Added guilty code to a copy of bugzilla home page.

http://ksu.kas.com/nsbug1c.htm (screenshot http://ksu.kas.com/nsbug1c.gif)
     More complex example in which another fixed DIV is first rendered, and
     then the contents overlaid.

http://ksu.kas.com/nsbug1d.htm
     Demonstrates that LAYER causes the same problem.

One possible fix would be to use the page background color as the default for
fixed elements whenever no background is explicitly specified.

Comment 1

[Patrick C. Beard]

Confirmed on Mac OS tip as of 8/31/99.

Comment 2

[Hixie (not reading bugmail)]

Known limitiation. Dup of bug 4209.

*** This bug has been marked as a duplicate of 4209 ***

Comment 3

[Chris Petersen]

Agreed. This is a duplicate of 4209.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8ca80f608348
[components] for https://github.com/mozilla-mobile/android-components/issues/12065: add a SyncStore and some initial state properties