Ars Technica’s Ryan Paul has posted a good piece on an alarming story: The developers of two popular and useful Firefox extensions, NoScript and AdBlock Plus, descended into an ugly squabble that involved each one attempting to interfere with the other’s operation–and which eventually led to NoScript having secret features designed to futz around with AdBlock Plus, if it was present. In a roundabout way, the ugly situation did Firefox users a service by making clear something which many of us didn’t know: Firefox doesn’t do enough to draw boundaries between extensions that prevent them from interfering with each other. The good news is that Mozilla is reacting to the tussle by establishing guidelines for what extension behavior is and isn’t kosher. NoScript’s developer has published an apology and agreed to follow the new rules. And I, for one, will be a tad paranoid from now on when installing new extensions–especially since the recent unpleasantness involved not obscure rogue add-ons but two of the best-known Firefox enhancers on the planet.