In a dashboard filter, you have an option to select a single value from the menu.
This mode of dashboard controls uses radio button choices to let the user select a single value.
In the dashboard's Edit mode, hover over a filter until its controls appear on the top right.
Click the icon (gear).
The Settings modal window appears.
In the Settings modal window, under Display Settings tab, check these options:
Make sure to de-select the following option:
Click Apply.
Manipulate the filter widget in the following ways:
In the state filter, click the (downward arrow) icon to open the menu of available choices.
The application control expands.
Notice that you can only select a single item from the menu.