Hello!

I crashed my mind while I experimented with draw filter :-)

I download sample UltraWinGrid_ActiveRow_Border_CS, upgrade this to 9.2 and add micro modifications:

a) change Rect to ClipRect in draw filter

b) add code to replace default black border color to light gray

this.ultraGrid1.DisplayLayout.Override.CellAppearance.BorderColor = Color.FromArgb(0xCC, 0xCC, 0xCD);

this.ultraGrid1.DisplayLayout.Override.RowAppearance = new Appearance
{
 BorderColor = Color.FromArgb(0xCC, 0xCC, 0xCD),
};

c) fix headers in the designer

this.ultraGrid1.DisplayLayout.UseFixedHeaders = true;

At last run.

As you see in process of horizontal scrolling overlapped gray rectangle has been appearanced. This unwanted rectangle around the active cell has been drawn at DataAreaUIElement level after borders drawn at RowCellAreaUIElement level. Color of this rectangle equals border color of CellAppearance.