Since upgrading my sites to 5.5.1, many times when I am editing a page, click Add Block, Content, instead of it bringing up the box to type, the "wait circle" spins forever.

I have about 10 sites on 5.5.1, have used several different computers, been at different locations (home, office, other offices), tried FF, IE, and Chrome (all latest versions), and it acts the same.

I will say that sometimes it just works great, but seriously more than half the time the wait circle thing just spins.

Anyone else seeing this?

I do have 2 sites still on 5.4.2.2 and they still work fine.

(other than this I 99% love the new 5.5.1)