MDI multi views

I'm writing an MDI project. I want to have multiple windows show different views of my data. Thus both of the view windows are connected to a single document window. Is it hard to open up another view window using MDI? I want to show simultaneously a window that contains a red square and another window that shows a green square. When I click in either window, I want the red square to become redder and the green square to become greener. I also want both of the boxes drawn using a CRect object tht is in the one document.

Thanks. I'm giving up right now on showing two simultaneous windows in SDI.