Hiding a main form without hiding a sub form

[cgeorgephilip]

In a C# form named Form1, I created an instance of an existing form named Form2 and made it visible using the code:
Form2 myForm2 = new Form2();
myForm2.Show();
It works fine. But when I hide Form1 from Form1, using the code,
this.Hide();
Form2 disappears if it is open.
(The same thing happens, if I hide Form1 from Form2,using a different set of codes)
Why does Form2 disappears when Form1 is closed? Any help would be appreciated.