Cannot change the project URL in project properties

Hello,

Currently when I debug my website in VS, I go to localhost:2043. I want to change it to mydev.com:444.

My URL field in the project properties is grayed out:

http://i.imgur.com/hD9dkgX.png

I have already edited my HOSTS file, but it still doesn't work.
I am using VS 2013 Update 1