The last, and quite possibly best, feautre of the event display is the
ability to get event information interactively. The syntax is simple,
type =<ctp variable>, and it will give you the current value of
that variable. For example, type =sntracks_fp and you should see
something like:
Expression = 1
Another example is =scal_et to display the total energy
deposited in the calorimeter. The possibilities are mind boggling...