Minimizing Forms

I currently have a project with the following configuration: one main
form and another (secondary) form. The second form has the minimize
button enabled. The problem is that when I click that button, the main
form remains at the same place and the second form is minimized ABOVE
the taskbar. I want both forms to minimize "into" the taskbar
(Application.Minimize). How can I do it?

Any suggestions/source code is appreciated.