Use this toPreview as you type (classic mode). The preview appears in a detached window that's shared by all documents.
Before invokingA document must be open to use this option.
Menu pathView > Preview > Active Preview Window (classic mode)
Command nameMViewPreviewActiveClassic
Accelerator keyC (from the main menu: Alt+V > I > C)
Options on parent menu (Preview+)Preview Tab, Active Preview, Active Preview Window (classic mode), Preview in Browser Window, Preview Server-Side Script, Preview through PHP Interpreter, Preview with Remote Files, Default Browser Window, New Browser Window