Unusually poor performance on Studio preview and test

[Ax1sAng1e (Pastor James)]

Severe lag spikes when moving the mouse in Studio

I’m now experiencing this as well. I first noticed it happening while in Test mode and doing firstperson/shiftlock and then quickly looking around, but it doesn’t happen in thirdperson. It seems like it lags whenever the mouse is moving over the viewport as long as you aren’t clicking on anything. Very strange, and very aggravating.

It has to do with some widget panel causing lag spikes?

This does NOT happen with a gamepad,
Moving around with a gamepad is smooth and responsive, this seems like mouse input only issue.