Hi all and thanks for your answers.

I've developed an MDI application with more than one toolbars and,
obviously, some diferent types of document. Let's call the type of the
documents as typ1, typ2, etc.

There is a toolbar that shold be visible only when the type of the
active document is typ1, but it should be no visible if the active
document's type is one of the rest.

Does anybody know how can I implement that? I supose I need to
overwrite some event which is called when the user activates a
document or something like that but I don't know which event should I
use?