Formbuilder generates extra radio button

I'm using the following code to create a yes, no, unknown field using FormBuilder. The data field is a char(1) in my database. I have the following lines in my dataobject class. However, the HTML created has a fourth radio button, without a label, before the others. ---partial listing of options set in data object--- public $y_n_u; // string(1) $this->fb_linkElementTypes = array('y_n_u' => 'radio'); $this->fb_enumFields[] = 'y_n_u'; $this->fb_enumOptions = array('y_n_u' => array('Y' => 'Y', 'N' => 'N', 'U' => 'U') ); ---HTML generated ----- <td valign="top" align="center"> <input name="test1_y_n_u_1" value="" type="radio" id="qf_51da48" checked="checked" /> <input name="test1_y_n_u_1" value="Y" type="radio" id="qf_47f93e" /><label for="qf_47f93e">Y</label> <input name="test1_y_n_u_1" value="N" type="radio" id="qf_4facaf" /><label for="qf_4facaf">N</label> <input name="test1_y_n_u_1" value="U" type="radio" id="qf_7a549b" /><label for="qf_7a549b">U</label></td> ----------------------------- Has anyone else seen this problem before? -A