I wanted to filter completed tasks in only one group. The workaround involves three rules and one filter.
- Create a new field called “Filter” and set two options “Complete” and “Incomplete”.
- Set a rule at the Project level using the “Customize” button in the upper right corner so that any new task added to the project is given “Incompete” in the “Filter” field.
- Then set two rules at the group level that you want to filter, add two rules, one where the “Filter” field is set to “Complete” when you complete a task. The other is where the “Filter” field is set to “Incomplete” when the task is incomplete. The two rules are needed in case you check a task as complete and then uncheck it as it remains incomplete.
- Then set a filter to the whole project to hide any tasks that have the “Incomplete” in the “Filter” field.
Note that if you are adding this to a project with tasks in it already, you will need to change the “Filter” field manually for the first go but then the Project task should add it for anything new.