This is a problem I've had with several different versions of After Effects, and on more than one computer and I haven't been able to find any information about it.
Sometimes, especially after RAM previewing, my comp viewer will turn blue and I can't see my work unless I'm at a different zoom level. Sometimes after a while another zoom level will turn blue also.
I see you have a Mac running AE CC 2014. If you're on Yosemite, you need to update AE so it works properly with AE. First thing to check.
I also see a frame rate of 23.98 in the preview panel. That's a non-existant frame rate in AE. It doesn't go by the mythical frame rate of 23.98, it uses the ACTUAL frame rate: 23.976. You should use it, too.