I'm not sure if this only is exclusive to my situation, but I've been dealing with some series problems after this last big UI change. I've been dealing with the following issues:
Interact with articles and organization trees
I have run into this issue as well though I am using Chrome on Windows
With the new UI update, I can't even update article parents without the page lagging out. Just horrible, sloppy UIX
I also experience tons of lag while trying to use the new editor, using the old one works fine, however. I use Chrome on a Windows Laptop.