Multi-Clienting

I've been doing multiple instances for the past couple months by closing ROBLOX_singletonEvent, but now, it just doesn't seem to work anymore. Whenever I try to open a third: first being the Roblox Player, Microsoft Roblox, and another Roblox Player (which used to work) it doesn't open another window. It just redirects me back to the original one I had open.

Does anyone know a way around it or if I'm doing something wrong?