the Function setBuddy() does't work

I write the code with the book <<c++ GUI programming whit Qt4>>

label = new QLabel(tr("Find &What"));
lineEdit = new QLineEdit;
label->setBuddy(lineEdit);


when i pressed Alt+W,the focus sholud have jumped to lineEdit field,
but nothing happened, why ?


My qt version: Qt 5.5
complier: windbg_x86 6.11.1

Where else in your program is the shortcut key is Alt+W defined and used?