Invisible form controls

[grenk]

Hey all, I'm new to Ext so I may well be doing the wrong thing. Anyway...I'm doing the following and when I do
objPage.show() the text field and combo box are invisible until I click on them. Seen this problem before? Any ideas?

objPage = Ext.DomHelper.append(this.objPlaceholder, {tag : 'div', id : 'page2'}, true);
objPage.hide();

objInputValue = new Ext.form.TextField({width: 60});
objInputValue.setValue('1000');
objInputValue.on('blur', function(){
alert('do something');
},this);

var tempStore = new Ext.data.SimpleStore({
fields: ['value', 'label'],
data : [['value1', 'label1'], ['value2', 'label2']]
});
objInputUnits = new Ext.form.ComboBox({store: tempStore, displayField: 'label', triggerAction: 'all', width: 60});
objInputUnits.setValue('value2');
objInputUnits.on('blur', function(){
alert('do something else');
},this);

objPageForm = new Ext.form.Form();
objPageForm.column({width: 90}, objInputValue, objInputUnits);
objPageForm.render(objPage);