How to add a Form into Tab control

Sometimes for reusing your old code you may want to add a form instead of a user control into a tab. To do so you need modify some properties of your form otherwise your form may not be showing properly.

The properties are:
FormBorderStyle = None; //remove the form border and title area, make it like a flat piece
TopLevel = false; //TopLevel control cannot be embeded
WindowState = Normal; //If you are going to set the Dock value, WindowState cannot be Maximized

The last thing is do not forget call form.Show(), otherwise the form is not going to render itself.