These web blocks will always work on pairs with the combo box or list box. For this example drag and drop the combo box to the screen , define its sources and create a local variable to link with the widget. Name this combo box because we will need its id. (To see other features that you can obtain using this component, please check the demo page available and its respective code also available on the forge)
Drag and drop your usual combo box
Assign sources and variables as you would do for a standard combo-box.