DoubleClick           ALT/S, CTRL=CONTROL/S, NAME/F

This command executes the defined action for DoubleClick as defined by the
user for files of the selected type.  In other words, it performs the same
action as if you, for example, double-clicked on a file.

You can use the ALT and CONTROL switches to have Opus execute the action
as if the alt/control keys were held down.