If you open the Plume Velocity Settings frame, close it, then reopen it, the right-hand optical flow figure stops updating as you change things and the left hand figure has a delayed update - e.g. draw a new ROI, click apply, nothing happens, then click to draw another new ROI and you will notice that the previous ROI flow vectors appear.
If you open the Plume Velocity Settings frame, close it, then reopen it, the right-hand optical flow figure stops updating as you change things and the left hand figure has a delayed update - e.g. draw a new ROI, click apply, nothing happens, then click to draw another new ROI and you will notice that the previous ROI flow vectors appear.