98895 - scroll position wrong when loading page or resizing window

Status: RESOLVED DUPLICATE of bug 19261

(Core :: Layout, defect, P1)

Description

[Wayne Davison]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.3+) Gecko/20010907
BuildID:    2001090721

Mozilla does not maintain the proper scroll position when a page is loading
images, or being resized.  For instance, visit this page:

http://www.clari.net/~wayne/scrollbug.html#8

Notice that there is an offset that should position the page at image #8.  Since
the images have not yet been loaded (and their sizes are not yet known) the
browser positions the page at the text for Image #8 and then the loading images
bump the page down so that image #4 (or so) is at the top, not image #8. 
(Putting the cursor into the address field and pressing return will take you to
the right spot on the page, but pressing reload often returns you to the wrong
spot.)

A similar problem occurs when resizing the page.  The page should be trying to
keep what's displayed on the current page visible (as much as possible), but
instead everything slides up or down, making it very hard to find your previous
spot (unless you just happen to be at the top of the whole web page).  A better
page to demonstrate this problem would be to browse a very large documentation
page, and attempt to make the window a little wider while reading somewhere near
the middle).

The underlying problem is that Mozilla (and other browsers) are not handling the
scroll position using the right idiom.  Typically an application will remember a
scroll-bar offset, and blindly apply that offset to the document position, no
matter how the length of the document changes.  A much better solution is to
make a note of what material is being displayed in the top-left corner of the
browser window (perhaps using a pointer to a DOM object with some kind of
in-object offset?) and keeping that position constant when the size of the
document changes (i.e. changing the scroll-position value).

Reproducible: Always
Steps to Reproduce:
(Mentioned above.)

Comment 1

[S. Malling]

Confirming scroll position bug. Changing from unconfirmed to new. Setting
severity to minor. sorry :)

I think that the resizing "bug" should be filed for itself as an enhancement,
since it given todays standard is what's expected from a (microsoft-standard
"yuk")* browser, but i see your point.

* note that statements made, are mine, and do may reflect mozilla.org's point of
view *lol*

Comment 2

[Marc Attinasi]

Moving Mozilla 1.01 bugs to 'future' milestone with priority P1

I will be pulling bugs from 'future' milestones when scheduling later work.

Comment 3

[Boris Zbarsky [:bzbarsky]]

*** Bug 153348 has been marked as a duplicate of this bug. ***

Comment 4

[louis bennett]

is this a dupe of bug 60307?

Comment 5

[Wayne Davison]

Yes, the first part of my bug report does duplicate 60307.  The only difference
I see is that I also mention a related problem where resizing the window causes
the current position in the page to move around.  Since bug 153348 was filed as
an enhancement request for the resizing problem (and marked as a duplicate of
this bug), I'd suggest reopening bug 153348 and then marking this one (98895) as
a duplicate of bug 60307.

Comment 6

[Andrew Hagen]

This bug is a duplicate of bug 19261 and bug 60307. Dup'ing to the lower bug number.

*** This bug has been marked as a duplicate of 19261 ***