It does depend how you have your dual monitor set up.
PD displays with me on a single monitor (as it is suppose to) and will not stretch over into the second monitor.
I'd rather operate PD on the first monitor and utilise my second monitor for other tasks while editing - opening an image editor, locating folders/video and image files.
Just a different perspective than what Georg (must be quiet on the Deutsch forum
)has given you.
Dafydd