I've create three form from the Form Designer, such as Form1,Form2 and Form3.
Form1 :
Command button1: hiden thisform and do form Form2
Command button2: exit program

Form2 :
Command button1: hiden thisform and do form Form3
Command button2: show Form1 and release thisform

Form3:
Command button1: show Form2 and release thisform

When I in Form3 and click the command button to back the Form2, the error message occur. (object Form2 is not found)

How can I solve the problem?
Thank you!