231134 - jakarta.apache.org - "position: fixed" breaks "scroll one page" logic

Status: RESOLVED FIXED

(Tech Evangelism Graveyard :: English US, defect)

Description

[Wellie Chao]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040113
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040113

In the page at http://jakarta.apache.org/cactus, scrolling down by a page does
not go down by the proper number of screen lines. It goes down by too many
lines, meaning that every time I press "Page Down" or the space bar, there are a
few lines that I do not see. I have to manually scroll line by line rather than
going page by page. The page works fine in Internet Explorer 6.0. It may have
something to do with frames, but I am not sure. The page does not seem to render
with frames in Internet Explorer, whereas it seems like there is a frame up top
and a frame on the bottom when rendered in Mozilla 1.6.

Reproducible: Always

Steps to Reproduce:
1. Go to http://jakarta.apache.org/cactus in Mozilla 1.5 or 1.6 (I tried both).
2. Scroll down page by page.
3.

Actual Results:  
You will notice gaps between the pages.

Expected Results:  
Mozilla should scroll down by a page and not skip over content. In fact, the
bottom line or two lines of the previous page of content should show on the top
of the next page when scrolling.

Comment 1

[Alfonso Martinez]

Mozilla is scrolling by one page each time, but due to the header and the footer
it doesn't seems so.
You don't see that in IE because it doesn't support fixed positioning and anyway
the style sheet avoids it anyway:
@media screen {
  body > #header {
    /* Hide fixed positioning from IE */
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1;
  }
}

I don't think that it would be possible to adjust the scrolling algorithm to
take into account any possible fixed element in the page (it doesn't have to be
at the top it can be 10 pixels from the top...)

Your best chance would be to contact the page author and explain them the
problem that this design arises for you.

finally: somebody that really understand how the scrolling and layout works in
Mozilla can tell the fate of this bug much better than me.

Comment 2

[Chase Tingley]

Wrong component -- it's not a frames issue.  -> Layout: View Rendering, although
I'm not positive that's the right spot.

Also, this affects page-up/page-down by clicking in the scrollbar as well.

Resummarizing slightly.

Comment 3

[Mats Palmgren (inactive)]

The scrolling works as expected.  Making the scrollbar account for fixed
positioned elements would be wrong.  The page should be redesigned so that the
"middle" part is also inside a fixed positioned container with overflow:auto.

-> TE

Comment 4

[Matthias Versen [:Matti]]

seems to be fixed