Picturebox mousemove event fired even when mouse not moving
Form frm = new Form();
            frm.Deactivate += new EventHandler(MDIChildDeactivate);
            PictureBox pi = new PictureBox();
            pi.Dock = DockStyle.Fill;

            pi.MouseUp += new MouseEventHandler(ImageMouseUp);
            pi.MouseDown += new MouseEventHandler(ImageMouseDown);
            pi.MouseMove += new MouseEventHandler(ImageMouseMove);
            pi.Paint += new PaintEventHandler(CanvasPaint);
            pi.KeyDown += new KeyEventHandler(ImageKeyDown);
            pi.KeyPress += new KeyPressEventHandler(ImageKeyPress);

            /////////////////////////////////////////////////////////
            pi.PreviewKeyDown += new PreviewKeyDownEventHandler(pi_PreviewKeyDown);
            /////////////////////////////////////////////////////////

            if (!IsTabbedMdi)
                frm.ClientSize = size;
            frm.AutoScroll = true;
            pi.Name = ProjectFileName;

            Panel pnl = new Panel();
            pnl.Dock = DockStyle.None;
            pnl.Size = WarpArt.Properties.Resources.GreyCheckerBoard.Size;
            pi.Image = WarpArt.Properties.Resources.GreyCheckerBoard;
            pnl.AutoScroll = true;
            pnl.HorizontalScroll.Visible = true;
            pnl.VerticalScroll.Visible = true;
            pnl.AutoSizeMode = AutoSizeMode.GrowAndShrink;
            pnl.Name = ProjectFileName;

            pnl.Controls.Add(pi);
            frm.Controls.Add(pnl);
            frm.MdiParent = this;
            frm.Show();