Hidden (attribute of property)
If set, the property input field is not shown, however it does appear in the XML returned by the web services.
<property name = NAME label = TEXT hidden = "hidden" >
When creating thumbnails for an image by using the imagecopyof attribute, the "thumbnail" property is usually set to hidden because it is automatically generated. There is no need to manually enter it in the form but it is needed in the thumbnails of icons list.
<property display="secondary" height="90" hidden="hidden" imagecopyof="image" label="Thumbnail" name="thumb" type="image" width="90"/>