12234 - make vertical scrollbar for web pages visible always

Status: VERIFIED DUPLICATE of bug 72540

(Core :: Layout, defect, P3)

Description

[karnaze (gone)]

Troy, about 6 weeks ago in your absence we (Peter, Rick, Vidur, Kevin, et al)
discussed the fact that we should be optimizing for long documents instead of
short ones. The following table will get get 2 reflows, one without a scroll bar
and then one with. It would be more optimal to do it the other way around. I
realize this causes some problems when the document is close to fitting without
a scroll bar, but in those cases it is probably not a big deal to just show the
scroll bar. This optimization would help large documents and especially those
with tables. In the case of tables with percentage specified widths, columns, or
cells, the win is much bigger, since the columns don't have to be rebalanced a
2nd time.

<table border height=1000>
 <tr>
  <td>hello</td>
 </tr>
</table>

Comment 1

[troy]

We do assume we'll need the scrollbar when doing the initial reflow. I suspect
that what's happening is that the initial reflow is just an empty body and then
we get an append which is where the table is added

Incremental reflow assumes the current scenario is (no scrollbar vs. scrollbar),
and it has to, because an incremental reflow shouldn't change the display width.
If it did then it would also be a resize reflow and that would cause problems

Things may get better when the content sink is changed to not buffer so much and
get things displayed quickly

Another possibility is that we use a mediator like mechanism to abort the reflow
once we see we need a vertical scrollbar and then restart. That might help

Marking it REMIND, because there is no immediate solution

Comment 2

[karnaze (gone)]

Reopening. The extra reflows are likely hurting our performance (versus Nav4.x 
and IE) on pages such as yahoo and others. The best approach would be to make 
the viewport scroll frame honor the following (overflow: scroll does work on a 
div).

:viewport, :viewport-scroll, :canvas {
 overflow: scroll
}

That way, we could be like IE and always display the scroll bar and avoid a lot 
of extral reflows.

Comment 3

[karnaze (gone)]

Reassign to evaughan.

Comment 4

[karnaze (gone)]

It is worse than I thought. Instead of 2x the number of reflows, I'm seeing 3x 
in Viewer. I'm not sure that Troy's comments are reflecting what I am seeing. 
In the following html, I am seeing a fully constructed table get reflowed 3 
times at 3 different available widths. 

<table border bgcolor=orange width=100%>
 <tr>
   <td>foo</td>
 </tr>
</table>
<div style="width:100px; height:700px; border:1px solid black">foo</div>

Comment 5

[Peter Trudelle]

Eric is in the middle of some high-priority accessibility 
infrastructure work, targetting moz0.9.1

Comment 6

[Peter Trudelle]

->moz0.9

Comment 7

[Kevin McCluskey (gone)]

*** Bug 13371 has been marked as a duplicate of this bug. ***

Comment 8

[Peter Trudelle]

Accessibility work is running late, pushing this to 0.9.1.

Comment 9

[Peter Trudelle]

->hyatt, since EVaughan says Dave had a fix for this that didn't help things
much, and so wasn't checked in.

Comment 10

[Chris Waterson]

hyatt, could you post your patch here? the scrollbar jitters drive me nuts, and 
I'd love to just play around with it for a while.

Comment 11

[David Hyatt]

What patch?  I don't know what this bug is even about (or why it was given to 
me).

Comment 12

[Chris Waterson]

Trudelle wrote:

> ->hyatt, since EVaughan says Dave had a fix for this that didn't help things
> much, and so wasn't checked in.

I think at one point you'd made it so that the vertical scrollbar is always
displayed, regardless of whether it's required or not?

Comment 13

[James Green]

Suspect this is Platform/OS All/All, marking so.

Comment 14

[karnaze (gone)]

Bug 94587 may be relevant (see the tail end of the 2001-08-10 09:44 comments).

Comment 15

[Jesse Ruderman]

*** This bug has been marked as a duplicate of 72540 ***

Comment 16

[Matt Perry]

v

Comment 17

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e2e6aaf22009
[components] Close https://github.com/mozilla-mobile/android-components/issues/12234: Show correct popup window animation when window does not fit desired orientation