I have always wanted the option to set my volume control to just default, so if I change what my default input or output device is I don't have to modify TLB's volume control at all, or have multiple bars.
Even an option to hide control when not set to active would work. I have multiple different audio devices I output to but I never use more than one at a time. Instead of having multiple volume controls always showing it would be nice to only see the current one that audio is playing through.