I am going to recommend you stop using CE and try either LocalDB SQL Express or install SQL Express 2014 and convert your database to SQL. CE is limited and frankly slower and underpowered compared to SQL.
PS. I am still looking. It is because of the Entity but I am converting your database to SQL so I can look at it in MSSMS to see whats going on.
Great tutorial for converting it to SQL express 2014
Scroll down in the tutorial for instructions on converting the SDF file.