I've seen a number of higher-level players select a number of gateways and morph them all simultaneously into warp gates. How do you do that? If I press the "G" button, it just starts one of them warping. Can they be set to all morph simultaneously, or are my eyes just playing tricks on me?
There's no way to do them all automatically. You just repeatedly press G really fast, or hold it down and let the keyboard auto repeat. (I'm assuming most pro StarCraft II players have a fairly low key repeat delay.)