Widget designer and event handlers

When developping our custom widget designer (with sereral drop lists), we used the refreshUI and applyChanges methods. The first one is called when the window is opened and the second is called when we click on the Save button. 

However what I would like is to call refreshUI also when selecting an element in a list... Is it possible? Is there a method to do that? 

Or am I forced to do a second views but in the case, would you have some examples codes?

Thank you