449082 - aElt is null after customize toolbar drag and drop actions

Status: RESOLVED FIXED

(Toolkit :: Toolbars and Toolbar Customization, defect)

Description

[Noah (NoahSUMO/SolidSnake) [:Noah]]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1a2pre) Gecko/2008080203 Firefox/3.0
Build Identifier: 

Open the customize toolbar dialog, drag a separator, for example to the bookmarks toolbar, to the far left before/in front of that toolbar. But don't drop it there, continue holding your mouse click then drag it back to the customize panel, hit done and see if any errors are in the error console.

I get: Error: aElt is null
Source File: chrome://global/content/customizeToolbar.js
Line: 680

I guess it could be happening if I hover over the very very edge of the toolbox during that process. No addons btw.

Reproducible: Always

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1] (away from Feb 12th - Feb 22nd)]

The error happens here and seems to be Windows only.

function isCustomizableToolbar(aElt)
{
=> return aElt.localName == "toolbar" &&
          aElt.getAttribute("customizable") == "true";
}

Comment 2

[mcdavis941 (sporadically reading bugmail)]

I'm still seeing (what I think is) the same error with 3.6 (release) on Vista.

STR:
1 - start with fresh profile
2 - only add-on is Console2 (add it through add-ons mgr search and install, turn off a bunch of nasty plugins, restart)
3 - configure Console2 to show all errors
4 - right-click toolbox to customize
5 - reposition customize window so the full tabstrip is exposed (not covered by customize window)
6 - slowly drag location bar down from #nav-bar toward customize window
7 - while still dragging, as the cursor crosses from the toolbox into the tabstrip area, the error message is displayed
7 - while still dragging, if you wiggle the mouse around that border, or even find the right spot and hold it there, you'll generate a continuous stream of the same error

Error: aElt is null
Source file: chrome://global/content/customizeToolbar.js
Line: 671

Same code as before, at different line now:

function isCustomizableToolbar(aElt)
{
=> return aElt.localName == "toolbar" &&
          aElt.getAttribute("customizable") == "true";
}

Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6

Comment 3

[mcdavis941 (sporadically reading bugmail)]

One of 525258 and this bug is a dupe of the other; calling the other a dupe since this one was filed first.

Comment 5

[mcdavis941 (sporadically reading bugmail)]

CCing Dao for awareness

Comment 6

[Dão Gottwald [:dao]]

Attachment: patch

The dragover event listener is added to the toolbox, but the toolbox isn't necessarily completely filled with toolbars. It can have a bottom padding, for instance, depending on the theme.

Comment 7

[Dão Gottwald [:dao]]

http://hg.mozilla.org/mozilla-central/rev/ae8e9a478541