Cannot display child context menu

Cannot display child context menu

I have something like this
QPoint globalPos = ui.lineEditA->mapToGlobal(pos);
QMenu mnumain;
mnumain.setTitle("Parent Menu");
QMenu mnuBooleanOperators;
mnuBooleanOperators.setTitle("Child Menu");
mnuBooleanOperators.addAction("Child Action A");
mnuBooleanOperators.addAction("Child Action B");
mnumain.addMenu
// ...
QAction* selectedItem = mnumain.exec(globalPos);
Now only Parent Menu shows up when I right click however I do not see the
Child Menu ? Any suggestions on what I might be missing ?