The question Google Chrome pinned to Windows 7 taskbar not opening under pinned icon was closed on Sept 3 as being a duplicate of Some taskbar pinned icons are duplicated when an instance of the application is running.
I don't think this is correct, as the "original" question asked about Windows 7 applications in general, while the so-called "dupe" specifically asks about Google Chrome, and has Chrome-specific solutions – and is in fact a very helpful question for people searching for this issue.
I've flagged the question, but I wanted to bring it up here also.