I have to switch userids a few times a day. EVERY time I try to change it is an ordeal. I have to wait 30 seconds to 2 minutes to get a "sign in as" box. And, half the time, it is just the white box (as shown below). About a a quarter of the time, it is a white box that shows the top half of the text but no ability to put in my userid. And, the last quarter of the time, it allows me to enter a userid.
Then, after entering a userid, I wait up to 4 minutes for it to come back with something so that I can move forward.
This has been happening since the December update but I am finally turning it in as a bug.