Not a very nice workaround is to find where the link is validated and call the FileHandler for the path and return your own filepath instead.
It's not nice, because on upgrade, the path will be different, so you would need to update the web.config as well.
The other - much better, IMO, way is to create a new TinyMCE button for email only and simply decorate the email field in the model with proper validation. But then, you need to tell your editors to use this field instead of the one from EPi link.
So no way to do this without writing code and releasing a new version of the site... Thanks anyway for a good idea!
Actually, there is a way, I've just realized this.
You can go to admin mode -> Config -> Edit custom property types -> XHtml editor and drag the old link editor. It has similar icon as remove link. In this one, you can set anything you like.
I have added a bug report to loosen up the validation some. I know that we did this during development but apperantly, it's still too strict:
Hi,
if we need to add a custom buttom to mailto wherein we will give a provision to editor to insert receipcent mail id, Subject and body of mail, so how to proceed for this
your assistance really appreciated.
Br,
Nilanjan Saha
Hi! Our editor wants to create a mailto link with subject and body in the link dialog (mailto:name@domain.se?subject=thesubject&body=Jag vill prenumerera), but EPiServer won't allow it saying that it is not a valid link regardless if we input it in the "email" or "external url" box. Do I have to create my own link dialog for the editor to be able to do this without using the XHTML editor?
Regards Christer