That error message also seems to have come up here: http://community.retool.com/t/cellchangehandler/13330/5
Let me know if these setups sound similar to yours, or if it's a completely different issue!
That error message also seems to have come up here: http://community.retool.com/t/cellchangehandler/13330/5
Let me know if these setups sound similar to yours, or if it's a completely different issue!