Closing the form when the user clicks outside the form

I have a scenario in which I have aform that contains a datagridview, 2-3 labels and text boxes ,1-2 buttons on the form.
This form opens as a pop up when click a button in the parent form.Now I want to close this form when the user click any where in the parent form.
I have tried using lostfocus event of the particular form .
Please send me suitable code snippets if possible or the approach to go about it.
Looking forward to a quick reply