The Quick Controllers filters issues in any other Quick Gadget shown on the same dashboard. The Quick Controller can be added to your Jira dashboard as any other Jira gadget.
You have different options to filter issues with the Quick Controller:
Operators (e.g. =, !=, <=, IN, IS EMPTY, CHANGED, …)
Options are available depending on the field you are using to filter.
Connect a Quick Controller With any Other Quick Gadget
Make sure that a group is set in the Quick Controller (e.g. Group 1)
Add any other Quick Gadget to your dashboard
When configuring the Quick Gadget, select the group you want to connect with (e.g. Group 1)