Grid answer option "0" causes faulty analysis table

If "0" (without quotes) is an option in a grid question, it seems that the analysis page gets the information wrong.
* The "0" option is left out in the table header.
* The answers in the first column are all set to 0. (Or maybe it's the column with 0 as header - they coincide for me.)
* Because one table header cell is missing, the other header cells are shifted, leaving one column of answers orphaned.
A screenshot of results is included.

I think I tracked down the unwanted effect to line 248 in components/grid.inc, but since I don't know much about how Webform works I can't suggest what to do about it.

Thanks for a great module.

//Johan Falk, Sweden