Cannot make a contribution if text/numeric field is not a whole number

When I use a priceset to collect a voluntary donation where the user can choose the amount to give, I create a priceset field of type "text/numeric". ( In addition to other priceset fields for other office-determined amounts).

The calculated total for the whole priceset always looks fine, even when the user fills in a donation amount of 45.50 ( or some other amount with cents). But upon clicking "Continue", the user gets the error message as follows:
------------------------------------------------
Please correct the following errors in the form fields below:
Voluntary Donation must be an integer (whole number).
------------------------------------------------

This error message also occurs when a user is trying to create a contribution in the back-office area with the same priceset. Other types of priceset fields do not get an error when using cents. ( ie I can create a checkbox priceset field with an amount of 34.50)

I have reproduced this issue in the public sandbox at:
http://drupal.demo.civicrm.org/civicrm/contribute/transact?reset=1&id=7

FYI: The priceset I tested with is at:
http://drupal.demo.civicrm.org/civicrm/admin/price/field?reset=1&action=browse&sid=12