185746 - vanishing scrollbar on fake-frames-in-CSS "position: fixed" page

Status: RESOLVED WORKSFORME

(Core :: Layout: Positioned, defect)

Description

[Jamie Zawinski]

The above URL shows an example of how to (purportedly) do frames-like things
using CSS.  It looks pretty good when you first load that URL -- but as soon as
you resize the window, the scrollbar vanishes.  Doesn't matter how you resize
the window, or even whether the width changes: making it wider, thinner, taller,
or shorter triggers the lossage.  You can still scroll the text by dragging a
selection with the mouse.

Hitting reload makes the scrollbar come back.  Resizing again makes it vanish again.

Mozilla 1.2
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2) Gecko/20021203
Red Hat 7.2

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

-> R & A Pos.  (Hmmm.  Maybe the intentionally-cryptic component name was a
little too cryptic.  But it's probably better this way.)

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: testcase

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

The only reason I can think of that this would happen is something weird with
the splitting of style data that makes us think that the Area frame (the frame
for the div inside the scrollport) is 'position: fixed' and thus doesn't count
for overflow.  However, I don't see why that wouldn't cause the same problem the
first time around.

(Of course, :-moz-scrolled-content inherits 'display', but not 'position', so it
shouldn't be a problem in the first place.  But I could imagine that causing
other weird problems.)

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

It's worth noting that triggering an incremental reflow on something inside the
scrollable div brings the scrollbar back, e.g., entering 
  javascript:void(document.getElementsByTagName("p")[0].style.width='400px')
in the URL bar.

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Works in an 11/13 build. Must be a regression, ergo probably my fault :-).

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Works for me in 2002121708 too (although the scrollbars look like crap which is
a new bug)

Comment 7

[Robert O'Callahan (:roc) (email my personal email if necessary)]

BTW I'm Linux+GTK.

Comment 8

[Jamie Zawinski]

For no reason I can really justify, I rewrote my bookmarks page to be frameless
in this way:

http://www.jwz.org/bookmarks.html

It works pretty well, except sometimes, in the right cell, no lines wrap,
causing a horizontal scrollbar to appear.  I *think* this no-wrap state is
triggered every time you resize the window.  Hitting reload causes lines to wrap
again, and the horizontal scrollbar to vanish.

Comment 9

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Oh, I just reproduced this.

Comment 10

[Ari Pollak]

I don't see the scrollbars disappear under Debian mozilla 1.2.1, but I do see
other weird behavior - a horizontal scrollbar appearing for no reason, half the
text stops wrapping for no reason, etc.
I should also note that the mouse wheel does not work in any pseudo-frames with
position: fixed.

Comment 11

[Felix Miata]

WFM in OS/2 trunk and W32 1.5.

Comment 12

[Anne (:annevk)]

Resolving WORKSFORME per comment 11. Please reopen if someone can still
reproduce this.