If there had been any docs released with this feature, I might have thought to look in the User Management, but this panel was staring me in the face when I enabled the plugin... It's a big waste of my time when you release new features and I have to GUESS how it all works!

There's no guessing. The validation for From already prevents anything more than digits. The validation for To could probably be improved, but at this time that page is reused by the mass messaging feature from CB > User Management so it can't validate only digits due to supporting a comma list when using mass messaging. Regardless both parameters directly ask for you to supply user id in their description. You're upset with me over something you've refused to read. If you won't read a description you assuredly won't read any documentation for it.

So... why is this new feature breaking our SEF? (or vice-versa...)

No idea, it works fine on our demo site with SEF and in my tests. It maybe associated with Joomlas language filter which alters URLs. Try disabling Joomlas language filter plugin in Extensions > Plugins then turn SEF back on and see if the issue persists.

Here is the profile: where is the 'new icon' for messages?

On your own profile on the far right of the menu bar where Edit is. If you disabled "Profile Icon" parameter within PMS > Parameters > Internal > Display > Messages; it's enabled by default. The alternative is you could have a fontawesome conflict; ensure you're using Fontawesome 4 if you've disabled CBs fontawesome otherwise ensure CBs is still loading in CB > Configuration > Integrations.


All of this you can test and see what to expect on our demo site directly, which is using defaults for the PMS plugin. Simply login as User. The new PMS notification is in the login module. Upon navigating to the users profile you'll see the new message icon on their CB menu. You can compare your configuration to the demo site as well (backend access is provided; see the Login As).

demo.cbdemosites.com/

I guess I need how to figure out how to implement a popup of some kind, conditional on new messages?

There is no popup feature. New message notification is shown in the CB Login Module and CB Workflows Module.

Documentation of all the various switches and settings would be very useful

The parameters already describe exactly what they do. We're not going to document parameter descriptions. Mouseover them and read them carefully. If any of them are unclear simply ask and we can clarify then improve them in a future release.

I do hope you get it published the same day as the official release of 2.3

There won't be documentation for this feature released same day as CB 2.3.

Does turning language filtering off resolve the issue? This wouldn't be an issue specific to that feature. It'd be a potential problem in our router being unable to determine what plugin you're trying to navigate to due to the URL being altered by Joomla. If disabling the language filter plugin resolves it then that'd certainly be a possible cause.