protected override void OnMouseDown(System.Windows.Forms.MouseEventArgs e)
{
float yPos = 1;
int curItem = firstItem;
float itemHeight = ItemHeight;
while (curItem < completionData.Length && yPos < Height) {
RectangleF drawingBackground = new RectangleF(1, yPos, Width - 2, itemHeight);
if (drawingBackground.Contains(e.X, e.Y)) {
SelectIndex(curItem);
break;
}
yPos += itemHeight;
++curItem;
}
}