The current design of the Application.enter/leaveNestedEventLoop() API implies that the leave...() call happens exactly for the most recent nested event loop. The following scenario isn't supported:

enter loop1
enter loop2
leave loop1 << --- not supported; should be "leave loop2" first
leave loop 2

However, there's a requirement to support this scenario for Plugin-related code.

We need to introduce EventLoop objects, so that the enter()/leave() methods would belong to these objects rather than be static Application class methods. In this case we'll be able to distinguish between the leave() calls so that the inner nested event loop won't terminate because of a call to leave() for the outer nested event loop.