I’m learning AC2006. 
I have been working with Layouts and Viewports.  I used to be able to click in a viewport and
activate it as current, then right click and I'd get a menu which included “Properties”.  But something happened (I must have clicked
the wrong thing) and now “Properties” does not show up on the right click
menu.  Also the Viewport “Properties” had
options for locking or unlocking what was to be displayed.  Now I’m trying to use the general “Properties”,
but it doesn’t have the same control.

Any suggestions?

Thank You,
Roger