Propriedade ToolStripItem.Selected

// This method defines the behavior for rendering the// background of a ToolStripItem. If the item is a// RolloverItem, it paints the item's BackgroundImage // centered in the client area. If the mouse is in the // item's client area, a border is drawn around it.// If the item is on a drop-down or if it is on the// overflow, a gradient is painted in the background.protectedoverridevoid OnRenderItemBackground(
    ToolStripItemRenderEventArgs e)
{
    base.OnRenderItemBackground(e);

    RolloverItem item = e.Item as RolloverItem;

    // If the ToolSTripItem is of type RolloverItem, // perform custom rendering for the background.if (item != null)
    {
        if (item.Placement == ToolStripItemPlacement.Overflow ||
            item.IsOnDropDown)
        {
            using (LinearGradientBrush b = new LinearGradientBrush(
                item.ContentRectangle,
                Color.Salmon,
                Color.DarkRed,
                0f,
                false))
            {
                e.Graphics.FillRectangle(b, item.ContentRectangle);
            }
        }

        // The RolloverItem control only supports // the ImageLayout.Center setting for the// BackgroundImage property.if (item.BackgroundImageLayout == ImageLayout.Center)
        {
            // Get references to the item's ContentRectangle// and BackgroundImage, for convenience.
            Rectangle cr = item.ContentRectangle;
            Image bgi = item.BackgroundImage;

            // Compute the center of the item's ContentRectangle.int centerX = (cr.Width - bgi.Width) / 2;
            int centerY = (cr.Height - bgi.Height) / 2;

            // If the item is selected, draw the background// image as usual. Otherwise, draw it as disabled.if (item.Selected)
            {
                e.Graphics.DrawImage(bgi, centerX, centerY);
            }
            else
            {
                ControlPaint.DrawImageDisabled(
                        e.Graphics,
                        bgi,
                        centerX,
                        centerY,
                        item.BackColor);
            }
        }

        // If the item is in the rollover state, // draw a border around it.if (item.Rollover)
        {
            ControlPaint.DrawFocusRectangle(
                e.Graphics,
                item.ContentRectangle);
        }
    }
}