Cannot set break point in animation state machine?

I find it not possible to set a breakpoint in state machine. When I right click, there isn’t breakpoint option in the context menu. It seems only available in event graph. How could I use breakpoint debugging animation state machine?

Thanks.

234759-2018-03-23-18-48-42-psmcharacteranimationblueprint.png

You may be able to watch the code run by selecting an instance when the game is running

Thanks, but it would be too quick to see. Further more I want to break to watch certain variable.