I have recently noticed (it might have been that way for some time but I hadn't noticed) that when I am logged into gmail using firefox, the address bar contains a grey triangle containing an "!" before the "https". When logged into outlook.com there is a green padlock.
When using chrome to access gmail there is a green padlock, and in IE a grey padlock that changes to orange as I hover over it.
I find it difficult to believe that gmail is not a proper secure site so is there something wrong with my firefox or machine?