Dual dialogue allows you to portray two characters speaking at once. Their lines display next to each other in the script.
First, write both characters and their dialogue, highlight both, and then click the dual dialogue button 
in the toolbar.
Alternatively, clicking the dialogue button at the start of an empty line will, or anywhere on a Character or Dialogue line will create text placeholders.
The editor will adjust the dialogue items to be side-by-side.
