Child controllers and size of subview

Hi!

I'm adding a child controller to a parent controller (which is RootController):

public override void LoadView ()
{
base.LoadView ();
var linearChild = new LinearChildController ();
AddChildViewController (linearChild);
linearChild.View.Frame = new RectangleF (10, 300, 300, linearChild.View.Frame.Height);
Add(linearChild.View)
}

What I want to do with this code is to "position" the child view inside a parent view hiearchy. The linearChild.View.Frame.Height returns 80, and this is what parent controller also sets for the frame. But the result is 100 (20 pixels more). And that is what is reported inside ViewDidLoad method of the child controller as well. If I change the Child Controller's view height to be 20px, the result will be 40 (again 20 more).

I don't know why this is happening. I can post the complete project if that helps.