OMGoodness! I have a customer that has this issue and it was a huge hinderance in her workflow. I could not recreate on any other Mac I had access to. It turns out I don't normally have the Control option on. By toggling it on I was able to recreate the blank preview. I also noticed that you don't have to toggle it off if you "undock" for lack of better term your working file. Basically I just grab my file window by the file name in the window and separate it from being nested with the tools and the preview is fine even with the controls being active in the background. I'm hoping this will help Adobe get one step closer to fixing it.
OMGoodness! I have a customer that has this issue and it was a huge hinderance in her workflow. I could not recreate on any other Mac I had access to. It turns out I don't normally have the Control option on. By toggling it on I was able to recreate the blank preview. I also noticed that you don't have to toggle it off if you "undock" for lack of better term your working file. Basically I just grab my file window by the file name in the window and separate it from being nested with the tools and the preview is fine even with the controls being active in the background. I'm hoping this will help Adobe get one step closer to fixing it.