The cause of this issue is that the webshell can't find a path to jquery.min.js, in order to fix this we need to point the webshell to a copy of jquery on the local server.
You can specify a different path (on the intranet) in web.config where you keep jquery.min.js.
Below is the app setting in web.config telling it to find the file in my bbappfx directory:
<add key="WebShellCdnList" value="jQuery=//localhost/bbappfx/jquery.min.js"/>
The default value for this app setting is "jQuery=//ajax.googleapis.com/ajax/libs/jquery/1.7.0/jquery.min.js".
Make sure you follow this format, and be aware that we are currently referencing 1.7.0, but you might need to make an effort to update your local CDN or the app setting if the application begins to reference a different version instead.