If I zoom back&forth I can see it again but when I move the cursor or hover over the comp won't let me see anything. Pretty annoying and stressing (on a tight schedule).
Seems that unchecking the "Reduce cache size when system is on low memory" preference helps with this problem. Now I can see my comp window again!
Thanks for sharing what worked for you with your fellow users. Please also file a bug report so that Adobe know about it too and can fix the issue so you don't have to uncheck that box in the future.
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