It is such a relief that plugin guis now stay on top of the mixer when you change something there. I also like how you can now use Alt-Tab (in Windows) to flick between Mixer and Project. Much more convenient.
If you have plugin guis open in the Mixer and flick back to the project to check something, the guis stay where they are, blocking the view.
Is it possible to put plugin guis on their own process (or whatever you did to the Mixer) or at least anchor them to the Mixer window, so when you flick back to the project you can actually see it?