WAB - persist data after panel is closed

How can I persist data after the panel is closed. It clears all choices made on forms.

Example1: a user selects a dropdown list item, if the panel closes and then reopens, the selection is not remembered. When the panel is closed I really just want the panel 'hidden' not destroyed.

Example 2: After the dropdown is selected a query task selects all features in a layer and is used to populate a list box. Can that query data be stored and used again when the form is closed and reopened. Or do I need to keep round tripping to server with a query each time.