protected void ResetBackRectBrush() { if(back_rect_brush != null) back_rect_brush.Dispose(); back_rect_brush = new System.Drawing.Drawing2D.LinearGradientBrush(new PointF(0.5F,0.0F), new PointF(0.5F, 1.0F), back_rect_c1, back_rect_c2); }