If you just add 'text' in this function in CreateDocx.php:
public function addStructuredDocumentTag($type, $options = array())
{
$options = self::setRTLOptions($options);
$sdtTypes = array('checkbox', 'comboBox', 'date', 'dropDownList', 'richText', 'text');
and then in CreateStructuredDocumentTag.php
if (isset($args[0]) && $args[0] == 'text') {
if (isset($args[1]['placeholderText']) && !empty(isset($args[1]['placeholderText']))) {
$sdtPr .= '<w:showingPlcHdr/>';
}
$sdtPr .= '<w:text />';
}
It's possible to add simple text inputs instead of only richText, and then tabbing between inputs will work fine.