584703 - XUL listbox vertical scroll bar misbehaving.

Status: RESOLVED FIXED

(Core :: XUL, defect)

Description

[Mike Kroger]

User-Agent:       Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2
Build Identifier: Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2

In an XUL listbox that contains more items than can be displayed, the vertical scroll bar indicates that there are no items below. Scrolling down, using the scroll wheel on the mouse, displays the hidden items, but the scroll bar won't work. I hope that makes sense?

Reproducible: Always

Steps to Reproduce:
1. Use an XUL listbox.
2. Fill it with more items than the vertical height can display.
3. Look an strange behavior of scroll bar.
Actual Results:  
The vertical scroll bar misbehaves.

Expected Results:  
The scroll bar should behave in the same way as any other scroll bar.

Comment 1

[Mike Kroger]

Sorry. Should have mentioned that problem occurs in Firefox 4.0b2. I have no idea what version to select from the version drop down, because, as usual, Firefox version numbers don't make much sense.

Comment 2

[Alice0775 White]

The following examples work for me on Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b4pre) Gecko/20100805 Minefield/4.0b4pre ID:20100805041002

https://developer.mozilla.org/samples/xultu/examples/ex_lists_2.xul
https://developer.mozilla.org/samples/xultu/examples/ex_domlists_5.xul

Comment 3

[Mike Kroger]

Alice, those examples work for me too. Maybe the problem only occurs when items are added using the appendItem method.

Comment 4

[Mike Kroger]

Here is an add-on that demonstrates the problem. Look at the listbox on the Load New Crosswords tab. Sometimes the scroll bar only paints after the window is re-sized.

http://www.wizzcomputers.com/crosswords31.xpi

Comment 5

[Alice0775 White]

Attachment: minimum testcase

listbox with minheight attribute causes v.scrollbar a misbehaving on 2.0b4pre.
There are two problems. The problems do not happen on 3.6.8.

Problem 1: Thumb height is incorrect.
[STR]
1. Scroll by mouse wheel and/or the following button

Problem 2: Scroll bar will disappeard at certain height of window.
[STR]
1. Scroll to top by the following button
2. Resize height of window very slowly

Comment 6

[Boris Zbarsky [:bzbarsky]]

Any idea when it broke?

Comment 7

[Alice0775 White]

(In reply to comment #6)
> Any idea when it broke?

Regression window:
Works:
http://hg.mozilla.org/mozilla-central/rev/a352d0413476
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a4pre) Gecko/20100318 Minefield/3.7a4pre ID:20100318124752
Fails
http://hg.mozilla.org/mozilla-central/rev/f4f2f895891e
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a4pre) Gecko/20100318 Minefield/3.7a4pre ID:20100318193205
Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=a352d0413476&tochange=f4f2f895891e

I guess landing of Bug 544472 causes the problems

Comment 8

[Boris Zbarsky [:bzbarsky]]

Yeah, quite possible...

Comment 9

[Neil Deakin]

Attachment: possible fix

Comment 10

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

Actually ... you need to do a loop over your children and do ConsiderChildOverflow as well.

Comment 11

[Neil Deakin]

Attachment: patch, v2

Comment 12

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

http://hg.mozilla.org/mozilla-central/rev/40f76b916195

Comment 13

[Firefox Bug Husbandry Bot]

Moving to Core:XUL per https://bugzilla.mozilla.org/show_bug.cgi?id=1455336