… doesnt seem to be working? trying to find the key command list for it to assign it again, anyone any ideas? when ive got the mixer open i can select tracks using left right etc, when im in arrange window i want up and down to be able to select audio tracks pretty sure it always used too not sure what ive done. played with the preferences section with the tick box to make up and down exclusive for selecting tracks, also no difference 
cheers
For me up/down move track selection, and shift up/down add one track up or down.
Check out your key commands, if you maybe use some other daws defaults or something.
It’s called Up and Down so search in commands, or in key command editor enter up key in field and search for what it does(button beside somehwere there).
cheers m8. found it in the commands, under navigate, when i search for up, or down it didnt find it though, weird so had to manually find it. all sorted now though, thanks