Like the button to open the ActionScripting panel.
It's right there on the Properties panel - all the way on the right side, second button down. Now granted, it's tiny and unlabeled, but still. I wish I'd known that was there ages ago! The way it works is that it opens the ActionScript panel for whatever symbol you have selected at the time. If you don't have anything selected, it opens the ActionScript panel for the current frame.
The more you know, eh? Maybe I'll turn into a clicker after all...and stop getting owned so hard in Wintergrasp. (Okay, okay, I'll stop with the in-jokes for you non-WoW geeks. At least I didn't work "for the Horde!" in there anywhere.)