allow-content-type config of ContentSelector is not working inside site config

[alansemenov]

allow-content-type config of ContentSelector in site.xml doesn't seem to work - it returns all elements.

site.xml:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<site xmlns="urn:enonic:xp:model:1.0">
  <form>
    <input type="ContentSelector" name="searchPage">
      <label>Search page</label>
      <occurrences minimum="0" maximum="1"/>
      <config>
        <allow-content-type>landing-page</allow-content-type>
      </config>
    </input>
  </form>
</site>

Same input works correctly inside a content type: