Adding Input Mapping Context goes in Player Controller. And every Input Action are inserted in my character class. Everything looks ok: declaration of IAs, binding actions to them etc… But alas, there is no response to my inputs.
Demonstration:
The question is: why is something like that happened?
Continuation. Of course, I tried to create the pure project. Just adding IMC without anything. And it isn’t being added. Why?
Seems to me you are not assigning your IMC to the c++ variable. In other words you need to make the c++ variable editable in BP then assign the IMC to that variable in the bp and it should work.
What do you mean? Asking that because I have the C++ variable in .h file
I don’t understand it 
Try to put AddMappingContext on beginPlay instead of the constructor.
It worked! Thanks very much <3