When clicking submit on the add extension screen, an error message pops up with the following error message:
Please specify a password for the XactView user or uncheck "Create User" under "XactView User Settings"
The tab containing the "Endpoint", "XactView Settings", "Device Options", and "Paging and Intercom" sections does not appear on the screen at all, even after the error pops up. The only reason the tab is visible is because the error forces the browser's view to the affected section. This allows you to finish adding the extension, but creates an extra step. This affects IE, Chrome, FF, and Edge.