The combobox component can be attached to the toolbar. Please refer to the code below. Make sure to download the latest version.
var toolbar = [{
text:'Add',
iconCls:'icon-add',
handler:function(){alert('add')}
},{
text:'Cut',
iconCls:'icon-cut',
handler:function(){alert('cut')}
},'-',{
text:'Save',
iconCls:'icon-save',
handler:function(){alert('save')}
},'-',{
type:'combobox',
data:[{value:'1',text:'text1'},{value:'2',text:'text2'}],
editable:false,
onChange:function(value){
alert(value)
}
}];