Click Create Parameter.
Hover over the new filter until the controls appear on the top right.
Click the icon (gear).
In the Settings modal window, switch to Values tab, and enter the following:
Under Output Parameter, enter dim.
Note that this is the parameter from Creating Visuals with Optional Dimensions.
Under Specified values, enter Value: country
, and Label: Country.
Click Apply.
In the Settings modal window, switch to Display Settings tab, and select the options Permit only one item to be selected and In single select mode, include a 'No Selection' option. Ensure that no other options are selected.
Click Apply.
Switch to application View mode, and select World Regional Populations.
In the Display Country Details filter, select Country.
Note that the table now has a new column, country.