Hi Nikita, just left-click one more time on one of those 4 corner icons, and the crosshair will jump to center.
To position the crosshair (or pivot scaling point) on the corner you want, left-click on the opposite one.

As far as I know, the smoothness of shaded models displayed in MoI is determined by Meshing parameters. You can adjust the Mesh angle in Options -> View. The lower the angle, the smoother the display. If too low, it could slowdown performance on weak system, I guess.