Tasks without dates: Creating a filter / view

[email protected] Sat, 23 Jul 2016 00:36:59 -0700 (PDT)

Newsgroups	gmane.comp.mozilla.devel.calendar
Message-ID	<[email protected]>

Hello,

I would like to filter for tasks that have no start and due-date. How can I archive that?
For filtering emails it is possible to create user-defined filters /views, how can I archive this for tasks?

I don't need a UI for that, I would be fine to write the filter "by hand".

Thank you very much,
Johannes