explorer dump in portal demo with Extjs4.2

[DazzlingBeing]

just run the portal.html in portal demo with firefox/chrome/ie.
when click the collapse button in Options panel, a dump occurs and javascript runs busy.
In firefox you can get this info:

ext-4.2.0.265/src/util/AbstractMixedCollection.js?_dc=1359626431069:390

use Extjs4.1, this will not happen.

[evant]

I don't see that in 4.2B2, nor in the latest code. I collapse/expand the accordion items, the west panel and the portlets, no exception is thrown.

[mankz]

I can reproduce this in Chrome, collapsing the west panel freezes my MacBook in Ext 4.2.0.265

[DazzlingBeing]

I try this with ie10/firefox18/chrome24 in window8, and my mates try this with ie8 in window xp, both are freezing the explorer.
The firefox forced stop the javascript and gave that info, it indicated the problem code is in ext-4.2.0.265/src/util/AbstractMixedCollection.js

[mankz]

Not reproducible in nightlies though, seems fixed!