Timeline Audio Track Folders/Grouping

I'd love to see a feature implemented that allows you to group audio tracks into collapsable folders to save screen real-estate. Having a folder for dialogue, music & SFX and being able to hide them when they're not needed would be a massive help in only having what you need on screen at any time. The parent track of each folder could show the combined waveform from it's child tracks. 

Any Reaper users will be familar with how useful this feature is.