Translate/Scale/Rotate along single axis using MMB jumps around erratically I know I can constrain a translate/rotate/scale operation along an axis by holding  MMB and also holding X Y  Z
But when I do that, the selected element jumps around erratically (along and outside the selected axis) when I drag the mouse.
Here is a gif of the problem
MMB is a shortcut to pushing X,Y,Z, don't hold any X,Y,Z key at the same time, just use MMB until the constraint is active, then let go of MMB. This should keep the movement constrained to the axis your mouse move along.