469487 - <tree> with negative margin on parent grabs mouseover/click from later element

Status: NEW

(Core :: XUL, defect)

Description

[Phil Ringnalda (:philor)]

Attachment: Example

The example is a somewhat-minimized version of Thunderbird on OS X's splitter between the folder pane and the thread and preview panes. Trying to approximate three-fifths of a native Mac "zero-width" splitter, which is visually 1px wide with another transparent 2px on either side, it's a box with -3px margin-right and a 1px border-right, followed by a 3px transparent splitter. In 1.8, that makes the border and 2px to the left act (for mouseover cursor change and click+drag) like the splitter, but on the trunk, only the border pixel reacts to the mouse.

STR:
1. Load example XUL
2. Mouse over the lime strip on the top half, watching the cursor change only for the rightmost pixel
3. Try dragging all but the rightmost pixel of the lime strip on the top half
4. Note that lime strip on the bottom half, which just contains a box instead of a tree, changes on mouseover for its whole width, and allows dragging for its whole width

bz said something about "display lists" and "roc" which hasn't yet been enough to tell me what in the last several years changed the behavior.

Comment 1

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

(In reply to comment #0)
> bz said something about "display lists" and "roc" which hasn't yet been enough
> to tell me what in the last several years changed the behavior.

Sounds like he was referring to bug 317375.

Comment 2

[(mostly gone) XtC4UaLL [:xtc4uall]]

works:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a1) Gecko/20060707 Minefield/3.0a1 ID:2006070704
fails:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a1) Gecko/20060708 Minefield/3.0a1 ID:2006070804

http://bonsai.mozilla.org/cvsquery.cgi?treeid=default&module=all&branch=HEAD&branchtype=match&dir=&file=&filetype=match&who=&whotype=match&sortby=Date&hours=2&date=explicit&mindate=2006-07-07+04%3A00&maxdate=2006-07-08+04%3A00&cvsroot=%2Fcvsroot

Comment 3

[Phil Ringnalda (:philor)]

Huh. Offhand I don't see what part of bug 201499 would have done such a thing, but thanks!

Comment 4

[Markus Stange [:mstange]]

Maybe the part that add the stack around the treerows, which adds another native widget (I think)?

Comment 5

[Neil Deakin]

It doesn't add a widget, but the contents of stacks get painted as if they were positioned elements, so the order in which the hittesting code sees the elements would be different.

Comment 6

[Ciprian Muresan [:cmuresan], Ecosystem QA]

Hi,

Considering that XUL is no longer supported in the latest Firefox release(44.0.2) or the latest Nightly (47.0a1) I will mark this issue as Resolved-Invalid.

Thanks,
Cipri

Comment 7

[Stefan [:stefanh]]

> Considering that XUL is no longer supported in the latest Firefox
> release(44.0.2) or the latest Nightly (47.0a1) I will mark this issue as
> Resolved-Invalid.

Firefox UI is made of XUL, and this is probably still an issue.