In my forum search, I also came across a post from Giles (aka @selig, long time, I hope you've been keeping well Giles

I've also noticed that VSTs, especially the resizable ones, tend to mess up the window and tab arrangement. Instead of popping open in a brand new plugin window, they will open in a new tab (in the rack) which totally messes up the window size of the rack, and I have to pop the VST3 out of the rack tab, and resize the rack window. This slows down my workflow quite a bit. Is there a way to prevent this from happening, or is this a bug?
So, if I could politely ask for someone to chime in here and offer a solution that allows for remembering the window layout and arrangement, it would be much appreciate. Even if this is not possible, at least someone could confirm this.
I also a few other questions and issues with regards to error messages upon booting Reason (like "Reason quit unexpectedly" multiple times, but Reason never actually quits, thank goodness), and a graphics issue that haven't been fixed, and in fact have gotten worse (which I reported to Props themselves, when Reason 12 was newer), but I don't want to muddy up this topic. I do plan on writing up a proper support ticket for these graphics issues especially, once I get a little more time.