sortables axis:'y' option => error C.originalPosition is undefined

sortables axis:'y' option => error C.originalPosition is undefined


Hallo,
When I use the option 'axis' and set it to 'y' on a sortable, and then
start dragging the element's handle, I get an error
"C.originalPosition is undefined" and the element disappears.
This works for another sortable though.
Any body know what the problem might be?
Thanks!