DbContext Generator/Reverse Engineer Code First features should generate POCOs with virtual properties to enable change tracking proxies
Currently, the EF 4.x DbContext Generator code generation item as well as the Reverse Engineer Code First menu item generates POCO classes that only have virtual on navigation properites. Hence, a lazy loading proxy will be generated for the classes at runtime. However, a change tracking proxy will not be generated. This causes performance problems if you have a lot of objects in the object context. Please at least add an option for making all the properties virtual, or, just make it do that by default.
Ladislav Mrnka commented
IMHO it is not needed. Classes generation process for both reverse engineering and DbContext generator can be changed directly in T4 template. Making those properties virtual is an easy change. If you have a problem with it ask a question on Stack Overflow and community will help you.
Moreover change tracking proxies are not considered as default solution anymore: