Code

private async void OpenSettings_Click(object sender, EventArgs e)
        {
            animationTimer.Enabled = true;
            await Task.Delay(3640);

            // setting button new
            GoBackSetting.Visible = true;
            GoBackSetting.Enabled = true;
            GoBackSetting.BringToFront();

            // setting button old
            OpenSettings.Visible = false;
            OpenSettings.Enabled = false;
            OpenSettings.SendToBack();
        }

        private async void GoBackSetting_Click(object sender, EventArgs e)
        {
            animateBack.Enabled = true;
            await Task.Delay(3640);

            // setting button old
            GoBackSetting.Visible = false;
            GoBackSetting.Enabled = false;
            GoBackSetting.SendToBack();

            // setting button new
            OpenSettings.Visible = true;
            OpenSettings.Enabled = true;
            OpenSettings.BringToFront();
        }

        private int _startLeft = -520;  // start position of the panel
        private int _endLeft = 46;      // end position of the panel
        private int _stepSize = 10;     // pixels to move

        private void animationTimer_Tick(object sender, EventArgs e)
        {
            if (!SettingPanel.Visible)
            {
                SettingPanel.Left = _startLeft;
                SettingPanel.Visible = true;
            }


            SettingPanel.Left += _stepSize;

            if (SettingPanel.Left > _endLeft) SettingPanel.Left = _endLeft;


            if (SettingPanel.Left == _endLeft)
            {
                animationTimer.Enabled = false;
            }
        }

        private int _startRight = -520;  // start position of the panel
        private int _endRight = 46;      // end position of the panel
        private int _stepSize1 = -10;     // pixels to move

        private void animateBack_Tick(object sender, EventArgs e)
        {
            if (!SettingPanel.Visible)
            {
                SettingPanel.Left = _endRight;
                SettingPanel.Visible = true;
            }


            SettingPanel.Left += _stepSize1;

            if (SettingPanel.Left > _endRight) SettingPanel.Left = _endRight;


            if (SettingPanel.Left == _endRight)
            {
                animateBack.Enabled = false;
            }
        }