title: VBA: Saving Excel form state
body: <p>I have noticed that some of the Excel Add-ins maintain state from one use to another. An example of this is the Solver add-in which will maintain form data even after closing and reopening the Excel spreadsheet.</p>
  
  <p>Where are the form elements saved such that the form can maintain state? I'm interested in emulating this behavior in a custom add-in and have not been able to figure out how to make it work. </p>