Is there a documentation how to use the Filter in the Web UI?
In particular I’m looking for an option how do exclude certain attributes.
E.g. project (including it’s child project) should not apear in my filtered list.
Are there options to sort the filtered list?
e.g. due date or priority or project and / or a combination of sort attributes
I found the section how to Setup filter 
May I add a question?
How to check against empty / not set Task Attributes?
I’d like to hide all Tasks without a dueDate and assumed the command would be dueDate != null
But null is not a vaild string.
What can I use here instead?
Try dueDate > 01/01/2000 - not sure about syntax on date part, but you get the idea.
got the idea.
has something like cheating 
I picked the date format syntax from the date picker:
dueDate > 1970-01-01 00:00
But this is not working as filter to hide tasks without a due date.
(same for removing the time).
Currently there’s no way to explicitly exclude tasks which don’t have a date set (like filtering for null).
This will be added at some point though.
