Complete Gmail Shortcuts

GMail has an inbuilt hack which I accidently discovered today, while I was chatting with my friend in the inbuilt gtalk in GMail. I can totaly imagine how Archimedes must have felt, but me being from 21st century, I am not that anti-social to run naked on the streets shouting "Eureka!!!". Instead, I'll share this accidental discovery. For starters, this doesn't work in IE or Opera or Safari.
Only for Firefox.
Ok, now login to your GMail Inbox . Now press, "Shift+?" (without the quotes, and the +,as in Shift and ? buttons together.I know you know, but for those who write back this doesn't work, I'm too lazy to write back.So read this PROPERLY). Did you see a translucent black screen flashed in your screen showing the entire GMail shortcuts directory written in white and yellow, as the one shown below?

There's also an option of opening in a new window, which takes you to this link.This pae contains the entire list in the tabulated format(for those faithful to IE).