I remember a while back there were a number of threads about no longer being able to select seats in advance on LH when flying on a UA codeshared number. Is this still in operation? I searched but couldn't find anything recent and this page (https://www.lufthansa.com/ge/en/seat-reservation) would appear to indicate it's possible.

There's a slightly odd but good deal I'm looking at booking, that only has the option for the UA codeshare for some reason but it's for the longest leg so I want to make sure I can select my seat.