Select the current Actor by clicking on its wireframe in the Working-Volume view windows.
The selection state of an Actor is indicated by the color it is drawn. A selected Actor is drawn in yellow.
Double clicking on an Actor will show an Edit Actor dialog. The contents of the dialog depend on the Actor type. For example, an Actor using a Model as a costume will have an edit dialog that allows the costume to be changed or to have a special effect added. All Actors other than the Camera can change the extent of their Costume timeline.