To run a macro when the GotFocus or LostFocus event occurs, set the OnGotFocus or OnLostFocus property to the name of the macro.
Remarks
You can use a LostFocus macro to validate entered data as the user moves the focus from a control. You can also reverse or change conditions that you set up in the object's GotFocus macro.
Other uses for LostFocus and GotFocus macros are enabling, disabling, displaying, and hiding other objects.
You can't use the CancelEvent action in a GotFocus or LostFocus macro.