UI looks bad for some time

When i add any node from outside the canvas for some time UI looks bad.

That’s the layout animation that you are seeing. You can disable it by setting AnimationManager.isEnabled to false. For example, during Diagram initialization:

$(go.Diagram, . . .,
  { . . .,
    "animationManager.isEnabled": false

If i use stop animation manager it solved my problem.

But many other issues are coming like.

May be ,If i stopped animation things are happening little fast.

Could you please describe what problems remain after disabling the AnimationManager?