So I have one new field when editing invoice, called invoice_quote_number, Right now is a text field to type in related quote number. If the invoice was created directly without being associated with a quote, this invoice_quote_number can be used to relate the invoice with a quote. I would like this to be a search popup that permits selecting a quote that are related to client of the invoice. Clicking on the quote will enter related quote number (quote id) in this field. Any suggestions?