Ability to collapse/uncollapse items in Priorities

[#1]

• Description: to have the ability to collapse/uncollapse items in Priorities
• Why is this feature important to you: Many of us will have several groupings under priorities, specially if we group by project. It will be useful to have the ability to collapse the results.
• How would you like the feature to work: to have a carrot icon in the top, similar to other groupings in WF, to have the ability to collapse/uncollapse all results at once.
• Current Behaviour: we can't collapse/uncollapse all results at once.