Currently, as a Roblox Developer having multiple Studio sessions open requires you to open Roblox Studio again and then open that place having two separate Studio sessions.
If you press ‘new’ it closes your current place and opens a new baseplate.
For me personally, this makes transferring of assets such as maps, scripts or just swapping between places more difficult and requires multiple windows being open at once (it’s a saviour that I have two monitors). It would be way more user friendly to just be able to tab between two different games you are working on (e.g. you need to make changes to different places).
If you’re inactive in one of the places if it’s in Team Create you could be disconnected until you reopen the tab.