Cannot generate definition of method to the cpp file

process:
1) Create new project (Qt Gui application)
2) Open mainwindow.h
3) Add declaration of public method "void foo()"
4) Generate definition Outside class
5) Add declaration of public method "void bar()"
6) I would like to generate a definition "void bar()" to the mainwindow.cpp but I can not. Can choose only those options:

• Add Definition in mainwindow.h
• Add Definition Outside class
• Add Definition Inside class