I have a combo box on a form, when a particular value (Rent) is selected another combo box is enabled and made visible. Rent is the default value but I don't want the second combo box to be visible until the user has confirmed that Rent is the value wanted.

Problem, if the user selects another option and returns to Rent the valid code is run, but if the user just tabs through the fields and accepts the default value the valid code isn't run.

How can I force the valid code to be run or is there another method I can/should use?

Sarah