current popovers hide the bottom of the container

[peterstadler]

thus hiding the identifier, see "Ebers" in A060147

[peterstadler]

still an issue when the title stretches over more than one line. see "Gutschmids" in A045245

[peterstadler]

it does work for "Deine beiden Briefe No 18 u 19" in A042755. Problem seems to be when the titles of the inner items have different length.