Hi guys, this is kind of a weird one, thought maybe someone else has run into this.
Setting up a site without a modal I have noticed that the command or control + click behavior doesn't trigger a new window with my view cart or add to cart buttons.
I don't have visible dev page to put this up on (I can pm you one if it helps), but if you look at this site from your case studies, http://willaskincare.com/products/face-friendly-clear-face-moisturizer/
it has the exact same behavior I am seeing on my dev site. Ctrl / cmd + clicking on the "checkout" or "shopping bag!" links in their header will open the page in the same window, where as any of the other links on the page will open in a new tab.
If you are on their hosted checkout or cart page the links behave correctly, only when cmd+clicking a link that takes you from the original domain -> the foxycart hosted page does it fail to open in a new tab.
However, middle mouse clicking behaves correctly, which is confusing.
I'm seeing in, FF Safari Chrome in both windows 7 and OSX
Commenting out foxycart.js seems to resolve it, so I would guess that something in the click handlers you are assigning is causing the change in the default browser behavior.
Anyway, thought it was interesting and would love to see if it was a resolvable issue.
Thanks! - joe