display problem first field in fieldset IE

[damien]

I have a form panel width 2 columns. Both columns have a fieldset. Problem i am having is that on all pages width a fieldset the first field is not correctly displayed in Internet Explorer. In firefox it works great. I have a picture attacht. As you can see the upper border off the firt field is not displayed. Thats the case for all pages with a fieldset on my website.

a little bit off the code:

var main = new Ext.Panel({
  labelAlign: 'left',
  title:false,
  layout:'column',
  items:[{
   columnWidth: .5, 
   bodyStyle:'padding:5px 5px 5px 5px;',
   layout:'form',
   items: [{
    xtype:'fieldset',
    title: 'NAW gegevens',
    defaults:{width:200},
    autoHeight:true,
    items: [{
     xtype:'textfield',
     fieldLabel: 'Voornaam',
     blankText:'Dit veld is verplicht',
     allowBlank:false,
     name: 'voornaam'
    }, {
     xtype:'textfield',
     fieldLabel: 'Achternaam',
     blankText:'Dit veld is verplicht',
     allowBlank:false,
     name: 'achternaam'
    },{
     xtype:'textfield',
     fieldLabel: 'Straat',
     name: 'straat'
    },{
     xtype:'textfield',
     fieldLabel: 'Huis nr',
     width:60,
     name: 'huisnr'
    },{
     xtype:'textfield',
     fieldLabel: 'Postcode',
     width:60,
     name: 'postcode',
     vtype:'postcode'
    },{
     xtype:'textfield',
     fieldLabel: 'Plaats',
     name: 'plaats'
    }]
   }]
  },{
   columnWidth: .5, 
   bodyStyle:'padding:5px 5px 5px 5px;',
   layout:'form',
   items: [{
    xtype:'fieldset',
    title: 'Algemeen',
    defaults:{width:200},
    autoHeight:true,
    items: [{
     xtype:'textfield',
     fieldLabel: 'Telefoonnummer',
     allowBlank:false,
     blankText:'Dit veld is verplicht',
     maxLength:11,
     maxLengthText:'Telefoon nummer mag met verbindings streepje maximaal uit 11 karakters bestaan.',
     vtype:'telefoon',
     name: 'tel1'
    },{
     xtype:'textfield',
     fieldLabel: 'Telefoonnummer',
     blankText:'Dit veld is verplicht',
     maxLength:11,
     maxLengthText:'Telefoon nummer mag met verbindings streepje maximaal uit 11 karakters bestaan.',
     vtype:'telefoon',
     name: 'tel2'
    },{
     xtype:'textfield',
     fieldLabel: 'E-mail',
     vtype:'email',
     name: 'email'
    }]
   }]
  }]
 });
 
var simple  = new Ext.FormPanel({
  labelAlign: 'left',
  title: 'Klant',
  iconCls: 'icon-form',
  frame:true,
  tools:[{
   id:'help',
   qtip:'Uitleg over deze pagina',
   handler: function(event, toolEl, panel){
    help();
   }
  }],
  buttonAlign :'right',
  width: 720,
  items:[main],
  buttons: [save]
 }); 

[issameddine]

Hello
tries to use the default theme for ExtJS