For Xhtmlstring property, in the Tinymce editor.
When creating an external link with the same hostname, it turns into an internal link when looking at the link again.

Even if a user specially wants to specify them as external links.
This behaviour is sometimes unwanted, and currently there is no way to have any control of it. (this is a second Epi project, where there is such problem)

Could we have any setting, that would allow to modify (or just disable) this automatic behaviour?
It could be a global settings in configuration file, but maybe best would be to add a checkbox near the external link - 'lock as external link' (UX -> a little lock icon).

Steps to reproduce:
1. In edit mode on a xhtmlstring property, in the Tinymce editor, create an external link to a page on the same site. For example, if the site is test.local, you add an external link to test.local/alloy-plan
2. User checks the checkbox 'lock as external link'.
3. Publish the page.
4. Go back to edit mode.
5. Edit the link.

Actual:
The Page radio button is selected

Expected:
The external link should remain as selected (as user 'disabled' conversion to internal link)