on window close with tabpanel which is not rendered: container is null or not an object

What steps will reproduce the problem?
1. create a window with tabpanels
2. place on the second tab a numberfield
3. open it but not view the second tab
4. call window close

What is the expected output? What do you see instead?
1. normal closing
2. i get the error "container is null or not an object" its on the first 
item (in my case a numberfield)

What version of the product are you using? On what operating system?
2.0.5?
WinXP
IE7 + shell

Please provide any additional information below.

workaround:

select the second tab at startup the window:
        DeferredCommand.addCommand(new Command() {
            public void execute() {
                tabs.setActiveItem(1);
                tabs.setActiveItem(0);
            }
        });

the error is thrown at this piece of code: "item.container.up('.x-form-
item')" on my first numberfield

    /**
     * This method will go back to a FieldSet or FormLayout are remove 
the 
     * form labels.  Otherwise, removing the just remove the field and
     * not the label.
     */
    private native void setDestroy()/*-{
        this.@com.gwtext.client.widgets.Component::addListener
(Ljava/lang/String;Lcom/google/gwt/core/client/JavaScriptObject;)
('beforedestroy',
            function(item) {
                if (item.isFormField) {
                    $wnd.Ext.destroy(item.container.up('.x-
form-item'));
                }
            }
        );

    }-*/;

Original issue reported on code.google.com by nietz...@gmail.com on 12 Mar 2009 at 10:13

sjivan / gwt-ext

on window close with tabpanel which is not rendered: container is null or not an object #479