[Content Area] Error "Unable to get property 'className' of undefined or null reference" when changing Display Options of content item

Steps to reproduce

1. View a Content Area property (e.g. Large Content Area of Alloy Meet page) in OPE mode - do not open fly-out editor
2. Change Display Option of a content item inside Content Area property between Narrow/Wide/Full --> Error below in browser console window
SCRIPT5007: Unable to get property 'className' of undefined or null reference
File: dojo.js, Line: 15, Column: 97154

Notes:
_ Not happen when change option to "Automatic"
_ Not happen when changing in flyout editor or All Properties mode

Triage note: Seems we're trying to set classes on destroyed widgets