Installed the Join plugin and creating a "base" job with Post-build Actions and listing other Projects to Build.

Click Add post-build actions, I see "Join Trigger" on the menu along with other actions.  If I click Join Trigger, nothing happens.  No config settings appear on the UI which should allow me to specify the Project to build.....just nothing happens.  

I've tried to downrev Jenkins to previous version and tried creating another blank job from scratch.  No change.