Use this toPreview within editor window in Preview Tab.
Before invokingA document must be open to use this option.
Menu pathView > Preview > Preview Tab
Command nameMViewPreviewTab
Accelerator keyT (from the main menu: Alt+V > I > T)
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