Actually, double-click was invented at Apple in 1980 or 1981, some ten years after the WIMP paradigm was invented at Xerox, and 18 years after Ivan Sutherland invented a sort of graphical user interface for Sketchpad, which Alan Kay credits as "the invention of the GUI".

See http://www.folklore.org/StoryView.py?project=Macintosh&s..., in the comments: "I remember when Larry was doing that testing. One of the things he tested was the three-button mouse, which is what Xerox had used. He found out that inexperienced computer users (the market that Lisa was aimed at, believe it or not) got too confused -- they couldn't remember what each of the buttons did. Same problem with a two-button mouse. So the one-button mouse was born. Of course, that meant that we needed double-click and triple-click, but that's another story..."

http://www.folklore.org/StoryView.py?project=Macintosh&s... shows screenshots of the UI that had the first double-click interface, in 1980 or 1981.

That doesn't mean that Apple deserves a patent for every double-finger-twitch action in perpetuity, or that double-click doesn't logically follow from the reduction in mouse button count.

> That doesn't mean that Apple deserves a patent for every double-finger-twitch action in perpetuity,

And they don't, so why bring it up.

> or that double-click doesn't logically follow from the reduction in mouse button count.

Lots of things "logically follow", but only a few make sense. Figuring that out seems to actually be fairly difficult as the state of the art shows.

Of course.