"Manage Issue Types" changes cannot be saved when session language is german

Changes on "Manage Issue Types" cannot be saved. When submitting changes, all selected Issue Types move back to right box and System display (german) message, that at least one option needs to be selected.

Selecting a default Issue Type adds another message stating that only selected Issue types can
become the default.

Setting the system language to US english yields expected behaviour, changes can be saved without
messages and are permanent.