thanks for your answers.
1. How do i sort by multiple criteria in the event manager gui? Did you use a stable sorting algorithm? I ask, because this would make it possible to sort by multiple criteria by sorting several columns with inverse sequence. (en.wikipedia.org/wiki/Sorting_algorithm
2. ok, my intention is to select all entries in the past that have no event in the future (== old, passed events).
Or the other way round, select all entries that have an event in the future (== future events). Even if it started in the past. That means that there is no reason to mark it as out-dated, because it's still active. Eg. a birthday starts long time before, but should not be selected as old event, because it is still important.
It's clear that the recurring events can't be generated for all possible instances, but there is a property (start date + recurrence, or infinite) that could indicate if there is an instance in the future. And iff there is one, it is a future event (and must not be deleted for example)
Perhaps, an alternative to the selection is a filtering feature.