It would be nice, if you could comment the classes in the engine (and the editor).
The comments on the methods and variables are generally quite good (better in some areas than other). When reading through a part of the code, it would be useful to read a few sentences or remarks about the purpose of a class. Sometimes the class name alone is not context enough. Thanks!
/* What does this class do? */
class SomeClass : public Parent
{
...
}