I have to highlight in my task list offt some tasks as "inactive". The task is not completed and waits for an unknown time.
I have found a solution:
In the "Tasks filter" screen, a "Wait list" filter is set up under "Overdue and Today". This filter sorts the tasks that have "due date" = "0".
It is highly desired that this is solved with other means, for example a field in task "Inactive"
* If anyone is interested, I can give the statement as I've resolved it.