11430 - Fixed positioned elements bits are smeared during scrolling

Status: VERIFIED FIXED

(Core Graveyard :: GFX, defect, P3)

Description

[Patrick C. Beard]

Yet another scrolling bug. This page exhibits some really bad behavior on the
Mac as well. A related bug, #5194 exhibits incorrect layering/clipping on
Windows NT. BTW, this page also triggers a crash when attempting to scroll the
middle div, which demonstrated a bug in mozilla/layout/html/base/src/
nsPresShell.cpp, line 1369, which was dereferencing a NULL pointer.

Another problem with this page is that you can't correctly select the text in
the fixed position divs. You can select it blindly, and force a refresh, and the
selection will draw, but not during selection itself.

Comment 1

[leger]

Settin Platform to All.

Comment 2

[Patrick C. Beard]

I've only seen this happen on the Mac.

Comment 3

[Biswapesh Chatterjee]

The page is really messed up in 1999112508 build (WinNT SP5) - draws
differently (and incorrectly) every time. Problems include document being drawn
over the scrollbar, scrolling occuring where it should not and (in some cases)
crashing as well. Setting OS to all. Interestingly, the page (more-or-less)
renders correctly in M11 WinNT SP5.Scrolling seems to be a big problem with the
M12 builds.

Comment 4

[Hixie (not reading bugmail)]

This is probably related to
bug 4209: {css2} Fixed scrolling positioned elements have no background defined

On Win98 AppRunner 1999121508, it is the scrollbar bits that 'smear' --
suggesting to me that room is being left for the scrollbar bits, but the room
is left transparent, and the background is undefined as per bug 4209.

Of course, I may be totally off base here... ;-)

Comment 5

[Pierre Saslawsky]

This is now a platform specific issue. It works for me on the Mac while the
following problems can still be noticed on WinNT:
- When scrolling the text of the center element, the scrollbar is not refreshed.
- When resizing the window, you get a corrupted display in the 2 bottom fixed
positioned elements. You can also have some pieces of the sidebar appearing
inside the fixed positioned elements, making me think that the View Manager gets
confused again with the bitmaps.

Comment 6

[Patrick C. Beard]

Other than the problem of fixed positions floating over the scroll bars, I think
this is working much better than before, so I'd consider it fixed. We'll want to
watch for regressions.

Comment 7

[Hixie (not reading bugmail)]

Hm, with all due respect, it doesn't look fixed to me. Opening the page given
in the URL field, resizing the window, and scrolling, gave me smears and 
everything. Attaching a screenshot shortly. Reopening. Moving to M14.

Comment 8

[Hixie (not reading bugmail)]

Attachment: Screenshot with Win32 2000012108 nightly build. Opened test page, resized, scrolled.

Comment 9

[Patrick C. Beard]

This is working on Mac, but seems to be broken on Linux. I fixed this on the Mac 
but not actually scrolling the bits if the clipping of a widget is complex, but 
just invalidating.

Comment 10

[Stuart Parmenter]

this looks ok on linux as i showed you earlier beard.. you can have it back ;)

Comment 11

[Patrick C. Beard]

Fixed by nsViewManager2.

Comment 12

[Hixie (not reading bugmail)]

If one resizes the window on Win32, then everything smears. Is this a new bug
or the same bug?

Comment 13

[Hixie (not reading bugmail)]

Ok, verifying fixed and opening new bug 28742 to cover this last issue.

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e3f01a340338
[fenix] For https://github.com/mozilla-mobile/fenix/issues/11430 - Gives enough padding to the tab tray give adequate space for the fab