How about a Mission Editor tip of the day thread?
I'll start with this one: Because of the background online map, the ME can take up to a minute to load. However, if you temporarily disable your internet connection, the ME will load in only a few seconds. The drawback, of course, is that instead of the detailed background map, all you will see is a plain black background. All of the other icons and graphics work just fine, though.
From the readme:
For faster ME loading times you can temporarily disable your internet connection but without internet connection you have only an ugly black background without map.