Sony vegas

[Teddybeer]

i don't know if i'm allowed to ask this question here
It's about edting a movie in sony vegas
i thought this forum might be better then OTL
i have a problem in sony vegas
the volume slider per track doesnt show anymore
normally i could adjust gain by dragging a bar from the top of the clip bar and adjust it all over the place
now i can't do it anymore for a reason i'm not aware of
can anyone help me????
Here is a screenshot i thought it might help

Spoiler!

First when i held my cursor in the spot where the arrow points, i saw a vertical double arrow which told me i was able to drag it up and down
i dont see it anymore
did i accidently press a disable button?

i hope im clear enough
if you have questions please ask