I’ve yet to find any place on the DxO web site for posting problems with the latest (purchased) version of the Nik Collection.
In the meantime, here’s my problem: I often use Color Efex and/or SilverEfex as smart filters with an image in Photoshop CC 2018 (5k Retina iMac running MacOS 10.12.6, with 64 GB RAM). It’s hard for me to pin down exactly why/when this causes PhotoShop to freeze, but it happens often. One time that it always happens is after I select a preset and then move the cursor to the right-hand adjustment panel to change a slider.
As for that pull-down menu, there is no + next to PhotoLab whether I use Safari or Chrome on my Mac. Finally got the + by clicking “back” in the pull-down men optionand now I got the full listing!