How To Handle An Open Document

[VictorN]

It is usually UpdateAllViews. Then in each View you have to implement (override) OnUpdate method that will be called in respond on the UpdateAllViews.
In OnUpdate implemetation you put some code to update current View using document data (via GetDocument method).
Have a look at the Scribble Sample: MDI Drawing Application and MDIDOCVW Sample: Demonstrates MDI Using Doc/View Architecture