what i found is, if u uncheck iCloud contacts under internet account, then it work fine, i can then forward a website using the share menu in safari or file using the share menu in the contextual menu(right click)
All others do work as example if you want to forward a website or a file to someone by email that works but with iMessage nothing happens.
I'm using Sierra on a iMac.
I created a new user using the same icloud account and apple id and it works fine, the small iMessage windows shows up when i try to forward either a file or webpage. I have deleted the new user following this since it was just to test if my user profile was damaged or something.
So still looking to resolve this issue in my original user profile