layout problems with extjs 4.1 in IE9

[Moinsen]

Hi,

i try to move from 4.07 to 4.1 and i have some layout problems.
This is my login form:

        
var loginForm = new Ext.form.FormPanel({           
  baseCls: 'x-plain',           
  labelWidth: 75,           
  defaultType: 'textfield',           
  items: [{              
    fieldLabel: 'Benutzer',               
    id: 'user',               
    name: 'user',               
    anchor:'90%'               
  },{               
    fieldLabel: 'Kunde',               
    id: 'company',               
    name: 'company',               
    anchor: '90%'              
  },{               
    fieldLabel: 'Passwort',               
    id: 'password',               
    name: 'password',               
    inputType: 'password',               
    anchor: '90%'                 
  }],
  buttons: [{
    text: 'Login',
    handler: function() {   }
  }]         
});

var loginWindow = new Ext.Window({           
  title: 'Login',           
  width: 300,           
  height:160,           
  closable:false,           
  minWidth: 300,           
  minHeight: 140,           
  layout: 'fit',           
  plain:true,           
  modal:true,           
  bodyStyle:'padding:5px;',           
  items: loginForm
});

loginWindow.show();

In Chrome it looks good but it don't works in IE. In IE i get these errors:

[E] You have set frame: true explicity on this component (window) and it does not have any framing defined in the CSS template. In this case IE cannot figure out what sizes to use and thus framing on this component will be disabled. 
[E] You have set frame: true explicity on this component (header) and it does not have any framing defined in the CSS template. In this case IE cannot figure out what sizes to use and thus framing on this component will be disabled. 
[E] You have set frame: true explicity on this component (button) and it does not have any framing defined in the CSS template. In this case IE cannot figure out what sizes to use and thus framing on this component will be disabled.

So there is something wrong with the CSS and IE9? Help needed, thanks.