Have a strange problem / bug in firefox (latest version 47.0.1 and 47.0.0).
I have 3 items in the menu, which are 3 different categories - Design, Photo and About
Design is the front page so works fine. But when i click 'Photo' or 'About' the colour doesn't change to the active link colour, and the same 'Design' page loads again, but curiously it displays the correct slug.
So just to to be clear: You are on the 'Design' page, you click 'About' and it re-loads the 'Design' page, but it updates the url to the 'About' page, and the active link on the menu stays on the 'Design' page, rather than moving to the 'About' page.
This is only happening in firefox, and only starting happening just now, it was working fine yesterday. The site works properly in safari and in chrome.