Why here if I open the SIP in a form, the events that is contained in another form with another object associated is fired?
Firstly I think you are confusing Form with Module, Forms have nothing to do with this. Event Subs belong to modules and are associated with Controls or Objects. Controls and library Objects belong to modules but are visible globally.
Changing the state of the SIP, wherever it is done, always causes the SIPChanged event which always runs any event Sub associated with it regardless of which module it is defined in.
You normally predefine Event Subs in the module that owns the Control or Object by "Sub Name_Event" and Basic4ppc automatically associates that Sub with the event. However instead, using AddEvent, you can associate any Sub, whatever its name, to an event and the Sub doesn't then have to be in the same module that owns the Control or Object.