Interesting that not even Raymond Chen knew about Shift+Click - i found it at some point years ago by trying random stuff on the Win32 controls and it was what i used to try whenever i wanted to tell if a program was using real Win32 controls or made its own since pretty much no toolkit had this behavior including Qt[0] :-P

[0] i think Qt might have added it at some point but it has been several years since i used Windows as a main OS and bothered to check it