Adding ForumURL To Links with no http://
 

I have been having a broken link problem recently, apparently if I click the button in Post New Thread to enter a link, and I delete the http:// part out of the pop-up box, then put whatever like aposidjfasd.com and save the post, if I go back and edit it, for some reason it is automatically putting the forum's base url onto the beginning of the link in the editor box.

I know the web browser will assume that the link is a path on the forum where the link resides and append that automatically but why is the forum software doing it?