sharke - that's encouraging - I must be doing something wrong, or have a setting wrong. Yes - when I select multiple notes, and adjust something it affects all notes. That works. Except when I try to trim using the trimmer down below in the velocity lane. As soon as I click to trim, it de-selects the notes, and the trim applies to every velocity.
Just to confirm - after you lasso selected the hihats, only the high hat velelocities show up in the controller lane (that's what I get too). Then you went down to the velocity controller lane and using left click and drag, you trimmed only the hihats? And none of the other midi velocities of unselected notes suddenly became visible as soon as you pressed down on the left click?