I cannot reproduce it, so take this for what it is worth.
I was very laggy (download in the background eating all of my bandwidth).
Opened a straw basket
Right clicked a fish and the "eat" box appeared on top of the night/day icon.
Went to click "eat," but ended up walking away from the basket (I may have missed it, not sure).
The "eat" symbol got stuck on the screen, un-clickable, and I lost right-click functionality. But I could still walk around and chat just fine.
I tried to reproduce it but failed. I even, around the same time, dropped some intestines on the ground and played around with them attempting to cause it again but was still unsuccessful.