Jacques Trépanier wrote:

If they don`t see the reminder and type in another application then
the reminder can' t be seen.

Perhaps I don't understand what you mean. When a reminder comes due, the
alert will appear on the screen and stay there. When a person returns to
their computer, the reminder will be staring them in the face. Certainly
they can ignore it and open another application, but that's a problem with
their behavior, not with Outlook's functioning.
--
Brian Tillman