Sometimes when working with multiply animations and switching through them in the action editor. The Keyframes stop displaying for certain action.
When the Panel with the action editor View is removed and added again, the displaying is working again.
This bug was seen in Version 2.76 and daily Build from 10/30/2015.
Fixed after closing and opening action editor view
My Project without Mesh. Bug is seen in walk_back_cycle action.
This bug is very annoying in my workflow.
Greetings and thank you for your work!