I have a form with a subform and subsubform

I have previously used a macro button on the subform to open the subsubform on the form (not the subform). Setting up the macro button allows me create a link between the subfrom and the subsubform.

I'd like to avoid using buttons and instead use VBA to open the subsubform by using a get focus event procedure related to a field on the subform.

Can anyone help please

Not sure to understand but a control in a subform that is not open cannot receive the focus.