So I've been experiencing some problems with the Views UI recently. (I know this isn't the Views Issue page, but its not an issue with Views, its an issue with jQuery Update that breaks views).
I was determined to figure out the cause of this problem as I have been using Views for a very long time and have never experienced such strange behavior. I copied one of my sites over into a new directory and I only enabled Views & Views UI. Everything was working as it should, so I started enabling custom & contributed modules one by one, to see what would break Views UI. After enabling all my custom modules, everything was still working as it should, then I enabled jQuery Update and suddenly everything broke and I encountered the issues I mentioned before. I have tested this using the most recent version of Views and the most recent version of jQuery Update and those issues definitely occur.
To get around it for now, I just disable jQuery Update when I need to work on any of my Views, and then re-enable afterwards. I just thought I'd bring this issue to the attention of the module maintainers.