Fix html generation errors for boolean options. Code was generating xhtml form for html4 output. In xhtml, Boolean attributes like 'disabled', 'required' are represented with a value that is the same as the attribute name. E.G. <input required="required" ...>. Html 5 (and 4) represents the same as <input required ...> . Recognize booleans in one of two ways: value is None value is the same as the attribute name Make html4 and xhtml variants of cgi_escape_attrs. Have input_htmlp4 and input_xhtml call the proper variant. Also set HTMLInputMixin property cgi_escape_atrs to select proper one similar to self.input definition. Then replace calls to cgi_escape_attr with self.cgi_escape_attrs to get correct output.

<!-- query.item -->
<span tal:condition="context/is_view_ok" tal:replace="structure
      context/renderQueryForm" />
<tal:block tal:condition="not:context/is_view_ok">
  <tal:block metal:use-macro="templates/page/macros/icing">
    <title metal:fill-slot="head_title">You can not view query</title>
    <tal:block metal:fill-slot="body_title">
      You can not view query.
    </tal:block>
    <td class="content" metal:fill-slot="content">
      You are not allowed to view <span tal:content="context/_classname"/>
      with id <span tal:content="context/id"/>
    </td>
  </tal:block>
</tal:block>