Script Editor Highlighting?

A while ago when I used Unity, I thought I remembered editing my JavaScript in just a little, external text editing window that popped up. Now, when I click 'open' Unity opens it in MonoDevelop(which I really don't like). Also, in MonoDevelop, or whatever other default program I set, the keywords like 'Update' aren't highlighted. Did the way you edit scripts in Unity change recently? Is there any way to get it to just open in that little window? And why aren't things like Update highlighted when I open scripts in other programs? Thanks :D