Window controls are not clickable from the very top of the window, they
have a margin to the top that makes them harder to click. Make them
clickable also from the very top to make them easier to activate.
The close button with the default windowcontrols_alignment=right
specifically is already clickable from the rightmost part of the window.
Partial fix of #9791 (other buttons also need to be updated).
Guido Cella
c9d2f17a98