I am having issues with 3.4 and didn't know if anyone else has seen this pop up, haven't been able to find anything searching around.

The container's cascade method is trying to access this.items.items... when is that ever something?

I think it is supposed to be var cs = this.items; but I can't verify this... it is posing an issue when trying to combine a panel with a window, but as an extended form popup class.

This is like what was done in this post long ago, but I can't see why it wouldn't still be a valid way of doing this.

http://northsideofthemoon.net/blog/2009/07/07/making-an-ext-panel-act-as-a-window-part-2/

I understand that this has been a part of the container for quite a while, and if you can explain I guess what it is doing, why and how I can determine the cause of the second items in items being null it would help.