The Image of "10 pin IDC connector" has the Key on the wrong side, for what is standard for IDC headers. It should be on the odd numbered side (1-9)
For an example See 3M's 8510-4500PL Data Sheet
http://www.mouser.com/ds/2/1/ts0413-65491.pdf
All other IDC headers on the site have it correct or don't show the keying.
Submitted an updated image file