Missing function and arguments in command completion when typing definition manually

// reproducable exmaple
// SomeClass.h header file
class SomeClass {

private:
    void myfunction(int arg1, double arg2);
public:
   void tryitagainfunction(int arg1, double arg2);
}

======================

// SomeClass.cpp 
// Type the following line (the function definition) manually.. 
// (NOT using menu option "Refactor->Add definition in SomeClass.cpp" )

void SomeClass::myfu<xxx>  
// type until <xxx> 
// you will see that the function "myfunction(int, double)" does not appear as suggestion in the command completion popup menu. (this is due to the "private" keyword

void SomeClass::tryit<xxx>
// type until <xxx>
// you will se that the function "tryitagainfunction(int, double) is listed in the popup menu of the command completion but if you select it (hit enter) then the function name is completed correctly but the function arguments are missing.