Fixup 04ece4f0: handle case where openinlined_ is not set

Fixup 04ece4f0: handle case where openinlined_ is not set

When computing the width of the button, some code has been added in
04ece4f0 to shorten the space in LeftButton geometry. It turns out
that the Left/Top-button-ness is not always known at this point (since
it depends on the width itself!).

Therefore, it is better to make the button narrower also in the
TopButton case.