Cascading input controls dynamically populate based on previous control choices—the value(s) selected in one control determine the values available in the next. For example, a report may be filtered on countries, states/provinces and cities. Using cascading input controls, the country(ies) selected in the first control determines what states/provinces are available in the second control, and the states/provinces selected in the second control determine what cities display in the third control. The user might then select one or more cities and then click the Run button to execute the report and see information concerning the selected cities.
A sample report using cascading input controls and named Cascading multi select example report is found in the Reports/Samples folder of the default organization if you installed the sample data.