We're all used to multitasking. Having many apps running on the go and many windows in each app. Maybe even having a window with a second operating system running in it and a whole more apps and windows.
In the context of that it's a bit of a limitation only being able to open one S3D window at a time. If one has more than one printer up and running and is preparing files for each of them, it's a drag not to have all relevent windows and settings open at the same time. Not unusual after a print is up and running to decide to stop it and review settings. Major drag if you've already started working on something else in S3D.
REQUEST: to be able to have multiple slicer windows open in S3D.