I'm trying to add a button to a select field, but no matter what I do the value label gets wrapped to the next row. When I don't set 'label' everything is ok, but then (obviously) the label is missing.

Screen Shot 2013-05-13 at 1.29.31 PM.png

Code:
xtype:'field',                        
component:{
         xtype:'container',
         layout:'hbox',
         items:[
             {
                    xtype:'selectfield',
                    name:'artist',
                    label:'Name',
                    store:'artistsStore',
                    placeHolder:'Select an artist...',
                    displayField:'name',
                    valueField:'name',
                    autoSelect: false,
                    flex:8
               },
               {
                    xtype:'button',
                    text:'+',
                    margin: 5,
                    flex:1
               }
   ]
}