Fix download archive menu for tree view.
Fix download archive menu for tree view.

This fixes the issue of the menu going outside of the main `container`.

8thcolor/eurucamp2014-htdsadr,8thcolor/eurucamp2014-htdsadr,8thcolor/rubyconfau2015-sadr,8thcolor/rubyconfau2015-sadr,8thcolor/rubyconfau2015-sadr,8thcolor/eurucamp2014-htdsadr