I think It could be nice of I could disable the moved your layer in time
when I left click it. Because I think its very seldom I would do this when Im animating. Its more possible that I whant to drag the tail and them accidentally moves the layer and bring my animation out of sync.
I instead think that you should have the tail drag effect no matter where you left click drag on a layer-
and if you alt left click on a head cell you could drag it in time forward an backward with out altering the time of the head cells before/after.
then you also would be able to drage your exposures when you have zoomed so far out on your timeline that you cant see the tail
maybe it also could be nice to here the sound when you were draggen so you could release yor head right on the sound you wanted
-mads