I'm getting a warning for my Wordpress install of CiviCRM, under the title Resource URLs: Make them portable:
Resource URLs may use absolute paths, relative paths, or variables. Absolute paths are more difficult to maintain. To maximize portability, consider using a variable in each URL (eg "[cms.root]" or "[civicrm.files]").
On the Resource URLs page it brings me to, I have the CiviCRM Resource URL as
http:// <path to Wordpress install> /wp-content/plugins/civicrm/civicrm
The others on this page which are populated are Image Uplaod URL
and Extension Resource URL
But when I try to change CiviCRM Resource URL to
which is the recommended portable value from the help button near the top, and then save it, the value is not saved, and reverts to the absolute URL above, and the warning persists.
I have installed CiviCRM 4.7.27 on Wordpress 4.9.1.