1) Try to disable all the third-party plugins and check if the problem persists. As I see there are errors in the console http://prntscr.com/egl3hn it caused the problem with frontend editor. But these errors appears even with the default theme. So, I suppose one of the plugins causes the issue.
2) Could you tell me what element are you trying to save and what option? I have tried test Static Block and did not face problem http://prntscr.com/egl0qp