Can't load custom template
The Selector.tpl is placed wrong hence its not invoked. It should follow exact path of CiviCRM core module
For example if the Selector.tpl in Core is placed under plugins/civicrm/civicrm/templates/CRM/Contact/Form/Selector.tpl than in template over-ride it should be /home/domain/testwpcivi/wp-content/uploads/civicrm/templates/CRM/Contact/Form/Selector.tpl
Once you have tpl placed under correct directory path clear civicrm cache