if filter list is longer than the page, it gets cut off sometimes

[steffchep]

Reproduce:

• Got o talks page (JL2017)
• filter by something like "Workshot Raum Juno"
• notice that the last Room "Java Innovation Lab" is now no longer reachable

Pointers: Menu has absolute positioning and its height is ignored - so this happens whenever the talk list is shorter than the filter list.