Quick Render (ActiveShade)

Main toolbar > Quick Render (ActiveShade) (on Quick Render flyout)

Keyboard > SHIFT+Q (Uses Quick Render mode currently active on toolbar)

The Quick Render (ActiveShade) button, available from the Quick Render flyout, creates an ActiveShade rendering in a floating window.

You assign which renderer to use for ActiveShade rendering in the Current Renderers rollout of the Render Scene dialog.