By default, a 0 is displayed in the challenged Id field in the Create Voter Cards and Select Precinct and Party windows. In order to enter a challenge Id, the operator may chose to either delete the 0, then enter the desired number, or enter the challenge Id, then delete the 0. The former seems more reasonable to me. Once the field is empty, however, the message 'Please enter a positive integer' is displayed.
Could this message be displayed only once the operator attempts to create a voter card or vote with a blank challenge Id?