Keyboard Shortcut To Switch Between Windows

[jdycus]

I would like to have a keyboard short cut that would allow me to change active windows. In other words, I have undocked the playlist & positioned it beside the main window. I would like to be able to press a single key to make the playlist window the active one and press again to make the main window an active one. I know this can be done by clicking with mouse, but I would prefer using a keyboard key instead of mouse. Thank you.