1.14 Track, Master Track and Mixer Panels: Tips and Layouts
REAPER includes a theme adjuster module which (amongst many other things) can be used to customize your track and mixer panel layouts.
Kind: concept (user-guide-section) Chapter: 1 Setting Up and Getting Started Source: REAPER User Guide v7.70

REAPER includes a theme adjuster module which (amongst many other things) can be used to customize your track and mixer panel layouts. It comes with three pre-defined layouts – A, B and C - for each of these. The default layout for the mixer is A, as shown above. The default layout for track panels is A when the mixer is displayed, B when the mixer is closed. Layout B shows all controls. To summarize: