Assignee → You can only have one “Assignee” filter applied, but the filter can include multiple (up to 5) people. If your filter includes multiple people, these people are “OR” -ed together because a task can’t be assigned to more than one person.
Completion status → Is either Incomplete tasks or Completed tasks. You can only have 1 completion status filter applied
Created on → The drop-down includes the following options:
Today
Yesterday
This week
Last week
Last 14 days
Over a month ago
Only one “Created on” filter can be applied.
Last modified on → The drop-down includes the following options:
Today
Yesterday
This week
Last week
Last 14 days
Over a month ago
Only one “Last modified on” filter can be applied.
Completed on → The drop-down includes the following options:
Today
Yesterday
This week
Last week
Last 14 days
Over a month ago
Only one “Completed on” filter can be applied.
Created by → You can only have one “Created by” filter applied, but the filter can include multiple (up to 50) people. If your filter includes multiple people, these people are “OR” -ed together because a task can only be created by one person.
Custom fields → Options include “Contains all” or “Contains any”
The timeline slightly evolved since I published this post. We ramped it up to 50% of users last week and we plan to ship it to all customers in the next 2-3 weeks!
It looks like people with comment-only access can only use the multi-filter in list and board view, but not in calendar view.
Can we change this?
We share a master calendar of events with clients; the list view is not helpful for them and using a filter in the calendar view would increase the functionality significantly. I’m really hesitant to grant edit access to any of them in case tasks get accidentally deleted etc.
I believe features like this usually make their way to My Tasks at some point, but I am afraid the My Tasks view is a “special” one which doesn’t make it automatic. Let’s see if Asana can provide more insights!
I love this! When will we get this kind of sorting for the Timeline view? This would be significantly more useful to me in Timeline so I hope it’s on the radar for a release soon!
Is this feature available on the “Team” Calendar as well (which showcases from all Projects belonging to a Team), or just on each individual Project Calendar?
Good question @Martha_Van_Houten. This update is only available on projects and (monthly) My Tasks calendars. We’ll keep you posted here if we plan to extend it to Team calendars in the future!
We want to filter a Calendar by a Custom Field (date), but when we do this, the Calendar places the task on the Due Date rather than on the Custom Field date - which are different. Is this a known issue to Asana?
Our use case is:
Our Tasks contain multiple dates: Filming date, Edit date, Publish date (all custom fields), plus the Due Date. We want to be able to filter calendar views for each of those dates.
It is indeed a missing feature, not a bug. We haven’t heard anything regarding this item and the roadmap. Asana doesn’t share its roadmap, like most tools in the same market.
I play for the “List” team myself 
