Sorry for posting this here and the K2 forum, I was not sure where it belongs.
I just installed the Allvideo3 to use with the latest K2 and now have the same issue which I had with SIG.
1. With the new dim setting on, I can't access the tabs in K2 item section. I disabled that feature in Allvideo and it worked fine. The same issue was with SIG Pro which I fixed by choosing a different display method in the plugin (slimbox-mootools)
2. Also, what ever changes were made in Allvideo3 created issues with the video from provider section.
It says to select a video provider but there is no drop-down menu to choose, just the field for entering the video ID