261411 - Scrollable <listbox> with overflow: auto and <listcol flex="..."> cuts widgets scrolled out of view, widgets overlap

Status: NEW

(Core :: XUL, defect)

Description

[Stefan Borggraefe]

Steps to reproduce:
1. Load testcase
2. Make your browser window small, so the scrollbar of the <listbox> appears
3. Use the scrollbar

Result:
The buttons overlap. When you use the scrollbar you can't see the part of the
button that was out of view. (Note: the scrollbar only appears with trunk
builds, FF and TB builds from the aviary branch don't show a scrollbar.)

Expected Result:
Don't let the buttons overlap. Show the part of the widget that overflows when
you scroll.

Source of the testcase:

<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <listbox style="overflow: auto">
    <listcols>
      <listcol flex="1">
        <listcell>
          <button label="I'm just a random widget."/>
        </listcell>
      </listcol>
      <listcol flex="1">
        <listcell>
          <button label="Make your browser window smaller and use the scrollbar
to see the bug!"/>
        </listcell>
      </listcol>
    </listcols>
  </listbox>
</window>

A construct like this is used in searchTermOverlay.xul and I ran into this issue
when I tried to add two buttons to it in bug 195224.

Comment 1

[Stefan Borggraefe]

Attachment: testcase

Comment 2

[Stefan Borggraefe]

CCing a "layout guy". Boris, do you know what is going on here?

Comment 3

[Boris Zbarsky [:bzbarsky]]

Nope.  I have no idea what the behavior of listbox is supposed to be; is it
documented anywhere?

Comment 4

[Stefan Borggraefe]

(In reply to comment #3)
> Nope.  I have no idea what the behavior of listbox is supposed to be; is it
> documented anywhere?

Hmm, according to http://www.xulplanet.com/references/elemref/ref_listcell.html
<listcell>s should only contain text. But in searchTermOverlay.xul and in the
attached testcase there are other XUL elements inside the <listcell>s. Is
xulplanet.com right? I couldn't find more information about this yet.

Comment 5

[Wayne Mery (:wsmwk)]

*** Bug 335258 has been marked as a duplicate of this bug. ***