Hi! I'm having some sizing problems when I put a fieldset inside another fieldset.
I'm using Ext 3.0.

Here's the code:
Code:
var win = new Ext.Window({
  items: {
    xtype:'fieldset',
    title: 'Fieldset',
    collapsible: true,
    autoHeight:true,
    items: [{
      frame: true,
      xtype: 'panel',
      layout: "hbox",
      autoHeight: true,
      defaults: {
        xtype: "container",
        flex: 50,
        layout: "form",
        autoHeight: true,
        defaults: {
          xtype: "textfield",
          anchor: "0"
        }
      },
      items: [{
        items: {
          fieldLabel: "Field A Label",
          name: "FieldA"
        }
      }, {
        items: {
          fieldLabel: "Field B Label",
          name: "FieldB"
        }
      }]
    }]
  }
});
win.show();
The desired behaviour is that the fieldset should resize to the width of the window, and the textfields should resize to fit the entire space, both with the same width.
The behaviour I get is that they get resized if the width gets bigger but not when it gets smaller.
Is it a bug or an error on my code? Does anyone knows how do I get the desired behaviour?

The code is based on the messages on this post:
http://www.extjs.com/forum/showthread.php?t=89466