Hi, ya, I can appreciate how confusing this can be to follow... especially since there's different behavior in each software.
I was just playing around in Modo, seeing if I can find something more specific in the behavior. I also tried to see if there's anything I could capture on video, but again, without seeing the physical mouse movement, you don't see the discrepency between the mouse vs the pointer.
But, I may be able to remedy that my 'narrating' the video, so you know what the mouse is doing at the time.
I don't think it's a CPU load, as both machines are sitting pretty much idle, aside from Modo running.
One thing I did notice this time around...
I grabbed an object, and carefully moved the mouse (repeatedly) left and right, left and right... which should cause the object to follow along, also moving left and right.
What I witness, is instead of moving left, right, left, right, left right... what it will do is... left, left, left, left, left, then finally right. The sync between the mouse drags vs the object moves is great (instant response, no delays). The 'delay' appears to be in when the drag direction is 'noticed'... So, the first few 'right' drags move left instead... but then (after a random number of drags drags) it recognizes the new direction, and the next drag is going the right way (again, totally in sync)... and (continuing the left/right mouse drags), the object will continue it's moves (in sync), but again moving in the new direction, until a random number of drags later, it recognizes the direction change, and does the next drag in the right direction. So, the 'stuck in one direction' thing is an ongoing issue, not just once.
Again, it's like the MOVEMENT is totally in sync, but the direction change 'signal' has a delay... or is only transmitted on random drags.
I tried with a different mouse, as the mouse I'm using is one that has things like DPI settings, etc... which I thought might be interfering (and maybe causing the weird 'exponential movement' thing... but my other mouse (which is more simple) did the same thing. I'll dig up a very simple mouse next, and see if that has the same behavior. I should also see if my tablet does the same thing (going though Mutiplicity, rather than directly connected to the Secondary, as it is now).
I'll see what I can do as far as creating a screen recording. I'll have to do some editing to it, and add a sync'd text 'narration', so you know what is going on.
So, for now, the summary (for Modo, at least), is:
-Multiplicity works perfect in Modo for everything except translation/creation (dragging to 'build') of objects. The mouse works perfect as far as interacting with the rest of the interface.
-Dragging an object/item in the 3D view results in movement that accelerates, rather than staying at a constant move rate.
-Even though the mouse vs object movement sync seems perfect (no delay), it seems like the recognition of a change of mouse drag direction only occurs on random mouse direction changes (as opposed to all).
-No CPU strain. This behavior happens consistantly, regardless of status inside and outside of Modo.