I have not seen this mentioned anywhere...but it might have been.
I have noticed an enhancement in 2019 that I must say...I LOVE IT! (And it's about dang time!)
Have you ever fired up Solidworks and got it started opening something rather large...and while it's crunching away trying to open it someone comes in and wants you to open something else? So you fire up another session of Solidworks...only to end up waiting for the OTHER session of Solidworks to finish opening before the newly launched session can finish launching?
Well...with 2019...you guessed it...you can fully launch more sessions of Solidworks even when another session is chugging away opening or rebuilding something.