I'm viewing the list of participants for the site on user/index.php?id=1. The settings block is un-docked. If I click on the "Move to side panel" button, I get an error:

You are trying to use an invalid course ID: ()

Stack trace:

• line 37 of /user/index.php: call to print_error()

I'm looking in user/index.php now to see if something is missing.