Upgraded to 3.1 (was upgraded automatically through my host, Dreamhost) and now my insert gallery into post button is gone. I used this feature literally every day so this is highly frustrating for me. The pictures upload ok and I can see them in the media gallery, but there is no way for me to insert a selection of them into a post.
Only plug-ins I have activated are Akismet and Lightbox. I've tried disabling all plug-ins, and the buttons still don't show up. All of the plug-ins are up-to-date.
I am using this theme but as far as I know it shouldn't make any changes to the admin area.