getForm() in keyup event returns undefined

I wonder if anyone can help me with the following issue:



I have a textfield in a formPanel, which is in turn in a tabPanel. When user types in this textfield, I want to its value displayed in another dislayfield. It works fine if I use id for both fields. But using id will prevent creating multiple instances of the formPanel object. Therefore I need to use field name instead. When I use the field name, I cannot use Ext,getCmp(), I use this.form.getForm().findField(). Then I get error-- this.form undefined. Does anybody know how to get around it? Many thanks in advance.



Regards

Guilan