default vs user event loops

[colinives]

I'm developing a new system and will be using event loops.

There application needs to make sure that some events have default actions but that specific modes take over handling this events.

What I need is to register a handler when in certain mode, de-register when that mode is complete but know that the event will be handled afterwards.

is there a simple way to make sure the default loop doesn't run when there is a user loop in place.

To me this type of functionality makes complete sense between user/default loops but they clearly run alongside each other.

Am I missing something with 'out-of'the'box' functionality or is there a simoklemapproach to make sure I don't miss events but that won't have events handled twice when a user-loop is registered.

I've runtime examples and ready all I can find but this area remains unclear.

Thank you