Suppose I have a class MyClass defined in MyClass.h and its implementation stays in MyClass.cpp. When writing code in MyClass.cpp, there's no code-completion popup window for its member variables (objects). For example, I have a private Gtk::Button _btnClose object in class' declaration (MyClass.h), and when operating with it in MyClass.cpp no completion is provided for it, although in MyClass.h it works perfectly.