For example if QTreeWidget  has top-level items "Father", "Apple", "Balloon", "Cat", "Acorn". 
Say "Father" is hidden. 

Now, when the tree has focus and you press "A" it selects "Apple" and if you press "A" again, it selects "Acorn". This is expected. 

Now, if you press "A" again, it doesn't select "Apple". 

If you don't hide "Father", it loops back and selects "Apple" when I press "A" for the third time.