I've been using Reaper with SpatSurround 12 moving the x and y values for the left input across the sound field using the ring/handle.
I've found that if I move the handle to my starting point and start the playhead the handle will jump away from where it was placed either to the centre point or to a random point. This even happens when the automation mode is set to write forcing me to edit the envelope curve to remove the blip left from repositioning the handle.
I've tried selecting the option in Reaper to "allow keyboard commands when mouse editing" but the handle jumps away even when hit go and I'm still holding the mouse button!
Is it possible to overcome this problem, maybe there is a setting that I've missed in Reaper? Any help with this would be greatly appreciated.