Tags are a great way to categorize and then filter your tracking links, tracking pixels and campaigns.
Once the tag is assigned to a datapoint you can select multiple tag to filter the results.
Once one or more tags are selected the Tags Dropdown displays the "Multiple tags" text and the tag icon becomes green.
It means that the results you see in the table are filtered.
To reset filters you can reopen the tag dropdown and hit cancel or you can click on the green tab icon.