Multiple instances of IDE

Quite often a programmer steals code from hist previous projects and as we can have multiple instances of our IDE open, it’s done easily.
But when working on a single screen and both IDE look exactly the same, sometimes I make mistakes by launching the wrong project or pasting at the wrong place.
It would be very handy if we could set different / temporary color-settings fro each instance of the IDE.
Does anybody know a trick doing this within one instance of Windows ?

I have to work with 2 IDE versions, too. After making mistakes I prefer to have only one IDE open.

Me too.

Even if you work with 2 screens, the focus jumps from one IDE to the other, on save, compile etc. . Working in two projects at a time is just very annoying.

I use 3 screen, and have this issue both with the Xojo IDE, and even more so with XCode, as there I will not only have mulitple projects but muliple sections within a project