The Report Viewer Configuration tab enables you to set the report viewer property Show Apply Button.
When set to True, reports with parameter options display the Apply button in the report viewer. When a user changes the parameter values, he must click Apply to render the report with the new values.
When set to False, the report viewer does not display the Apply button. Instead, when a user enters a new parameter value, BI Publisher automatically renders the report after the new value is selected or entered.
This property can also be set at the report level to override the system setting. For information on setting the property at the report level, see Configuring Parameter Settings for the Report in Report Designer's Guide for Oracle Business Intelligence Publisher.