Shift, just change:

Code:
if ($mouse.key & 2) {


To:

Code:
if ($mouse.key & 4) {


As for Fkeys, you can't see if an fkey is held down in the on hotlink event, but you can catch an fkey being pressed by using an alias:

Code:
alias F1 ; F1 is hit
alias F2 ; F2 is hit
alias CF1 ; Control+F1
alias SF6 ; Shift+F6