checkbox 0 becomes unselected when form validation fails

- create a binary poll with several choices
- set allowed choices to greater than 1
- submit poll
- go to poll node and vote on more than the allowed number of choices, including the first choice
- submit vote

you will get a warning that you have selected more than the allowed number of choices. but also, your first choice will have become unselected.

the values of the checkboxes default to the number of their array element [0,1,2,3,etc...] rather than their previously indicated status.