When I press shift back I want to go backwards a cue 100% of the time, I never want to stop an existing fade. When doing rapid edits I frequently encounter situations where I want to go backwards a cue and press shift back, but it just pauses the fade, or I think I'm fading an shift back twice to stop & then back, only to find I've gone backwards two cues. I see now reason for shift back to ever stop a fade, stopping is an operation activity, and cutting is an editing activity, there's no overlap.
