56876 - Scrollbar thumbs sometimes gets black gap (twips-to-pixel rounding error in widgets)

Status: RESOLVED WORKSFORME

(Core :: XUL, defect, P3)

Description

[Heikki Toivonen (remove -bugzilla when emailing directly)]

This happens on NT and Linux at least (me & jst). Not every time, though.

The thumb bottom "rounding part" and the long "trunk part" gets separated by a
black gap, 1px wide (haven't seen bigger). I don't see the gap when the thumb is
up, I only see it when the thumb is near the bottom of the scrollbar.

Comment 1

[Peter Trudelle]

->future, evaughan

Comment 2

[Jesse Ruderman]

Reminds me of bug 29949.

Comment 3

[Eric Vaughan]

This is somekind of roundoff error in the layout code.

Comment 4

[Eric Vaandering (no email)]

Attachment: Is this an example

Comment 5

[Eric Vaandering (no email)]

Attachment: Is this an example

Comment 6

[Eric Vaandering (no email)]

Is what I attached (twice, had a timeout) an example of what is being discussed
or should I open a new bug?

Comment 7

[Heikki Toivonen (remove -bugzilla when emailing directly)]

Your screenshot shows this bug. This is exactly what I see.

Comment 8

[John Morrison]

*** Bug 66113 has been marked as a duplicate of this bug. ***

Comment 9

[Peter Trudelle]

*** Bug 70786 has been marked as a duplicate of this bug. ***

Comment 10

[R.K.Aa.]

*** Bug 85087 has been marked as a duplicate of this bug. ***

Comment 11

[basic]

Is this bug modern only? Or does it also affect classic?

Comment 12

[Petrus Lundqvist]

It also affects classic. I think this is mostly noticable if you look at the 
column headers in the mail & news thread pane. Resize them a little and you 
will quickly see that some have a thicker margin than others.

Comment 13

[Petrus Lundqvist]

Much more evident than the scrollbar thumb are the column headers in things 
like the thread pane for mail & news. It's almost hard NOT to get some column 
header spacings render different (wider) than others. That's caused by the same 
bug as this - rounding errors.

Comment 14

[Ben Ruppel]

I can't seem to reproduce this anymore with builds from the 19th on win32. 
Perhaps it is fixed.

Comment 15

[Warner Young]

I don't see it now, either.  Maybe a result of the new theme simplification?

Comment 16

[Eric Vaandering (no email)]

I can't reproduce this on linux RC2. I'd suggest marking this WFM in a week or
so unless someone objects.

Per comment 13, I can still see small effects in the mail pane, but no where
near as distracting as this bug. That must be a different bug, right?

Comment 17

[Petrus Lundqvist]

The problem still exists. Defintely not fixed. It's the same roudning errors 
that are elsewhere in the UI too. It's the most obvious in the column headers in 
trees. For example, open Mail News and resize & play with the column headers a 
little in the thread pane and you'll quickly be able to get it so that some 
margins are 1 pixel wider than others. It's quite obvious and noticable. For 
scrollbars, it's not AS common but it definitely still happens.

Comment 18

[Sébastien Desvignes]

Attachment: Screenshot in Skypilot theme

I'm seeing a bug that I think is the same than this bug with the skypilot
theme:
the masthead image in mail/news don't line up properly with the toolbar. (see
attachment)
I'm using Mozilla 1.0 with a res of 1280x1024, note that on another machine
with res 1024x768, the image line up perfectly!
Using the DOM Inspector, I've found that in this case the toolbar height is
50px, and the computed image height is 52px which is bigger that it's
container!
(The source image is 50px of course)

Comment 19

[John Morrison]

*** Bug 158760 has been marked as a duplicate of this bug. ***

Comment 20

[Wayne Mery (:wsmwk)]

WFM - I don't see this in FF 1.5 or SM trunk or TB 1.6a aplha 2 22051206

Comment 21

[Wayne Mery (:wsmwk)]

Attachment: side by side compare from bug 66113

------- bug 66113 Comment #2 From R.K.Aa.  2001-01-21 04:32 PST  [reply] -------

this is a "sequential" error, best seen when using mousewheel to scroll a long 
page. Scroll down line by line and you see the bug appear - and vanish.
I counted it all once: The bug is "cyclic" - meaning that on the same page, it 
will after some 15 scrolls or so, repeat itself in an identical pattern. This 
bug has been around much longer than the newmod skin, i've seen it for a 
year, also seen when slider-button is not skinned.


WFM ?

Comment 22

[Wayne Mery (:wsmwk)]

WFM Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a1) Gecko/20060306 Firefox/1.6a1