The Electronic Frontier Foundation's "Stupid Patent of the Month" for December isn't owned by a sketchy shell company, but rather the Microsoft Corporation. The selection, published yesterday, is the first time the EFF has picked a design patent as the SPOTM. The blog post seeks to highlight some of the problems with those lesser-known cousins to standard "utility" patents, especially the damages that can result.

The chosen patent (PDF), numbered D554,140, would seem to be one of those things that's so simple it raises some basic philosophical questions about the patent system. That's because it's just a slider, in the bottom-right corner of a window, with a plus sign at one end and a minus sign at the other. That's it.

The patent was highlighted earlier on the blog of Sarah Burstein, a law professor at the University of Oklahoma who studies design patents and uses her blog to highlight some... interesting... examples. Many companies are getting design patents for things that are clearly functional in nature, like a Socket Wrench Tooth, or a rock dust blower, or even—really—a Quaker Oats granola bar.

Like a software slider allowing a user to zoom in and out, those things aren't new, and their designs don't seem particularly special. They're simply what's needed to do the job. It's hard to imagine how these documents push innovation forward in any way, but the fact that they are issued gives the companies who get them ammunition to pummel their competitors.

And it's serious ammo, since winning a case for infringement of design patents can lead to a damage analysis based on "lost profits," which can theoretically lead to a patent owner getting all of a defendant's profits.

"Putting aside whether Microsoft’s design was actually new and not obvious in 2006 (when Microsoft filed its application), whether Microsoft needed the patent incentive in order to come up with this design, and whether it is even desirable to grant a company a government-backed monopoly on a graphical slider (we don't think so, that's why this is a stupid patent), the scope of damages for design patent infringement has the potential to become a powerful tool to shut down legitimate competition," writes EFF lawyer Vera Ranieri.

And Microsoft has put the '140 patent into action, using it to sue Corel Software on December 18. In their complaint (PDF), Microsoft lawyers say that software like Corel Write, Corel Calculate, and Corel Show infringe nine Microsoft patents, of which four (including the slider bar) are design patents.

Microsoft's recent lawsuit is meant counter Corel's earlier one. Corel, which bought WordPerfect from Novell in 1996, sued Microsoft in July, saying that Microsoft Preview infringed on several Corel patents. Like many patent cases, Corel's complaint (PDF) can be summarized as "we lost, but it's someone else's fault." Corel lawyers write that "WordPerfect has been reduced to minimal market share as a result of Microsoft's aggressive actions."

"Microsoft's lawsuit is in direct response to the meritless claims made by Corel earlier this year in a Utah court," a Microsoft spokesperson told Ars via e-mail. "We are confident we will be successful." The spokesperson declined to comment on the EFF post.

The last time design patents were in the spotlight shone was during the widely reported 2012 Apple v. Samsung trial, in which Apple asserted that Samsung was infringing various kinds of its intellectual property, including design patents. That trial resulted in a jury award in Apple's favor of more than $1 billion, which was later cut down. This month, Samsung paid Apple $548 million, but it hasn't given up on the case. In fact, Samsung wants a hearing in front of the Supreme Court, and its argument hinges on design patents. Samsung lawyers argue that its relatively small design features shouldn't have led to such a large award, and it wants the Supreme Court to re-consider the law around design patents.

If the Supreme Court takes up that case, it will surely be the "big moment" for these odd pieces of intellectual property. Until then, those looking for wacky design patents should enjoy reading the EFF blog post and Sarah Burstein's Tumblr on design patents.