this.radSyntaxEditor1.SyntaxEditorElement.IntelliPrompts.OverloadListWindow.VisibleChanged+=OverloadListWindow_VisibleChanged;

        private void OverloadListWindow_VisibleChanged(object sender, EventArgs e)
        {
           ShapedForm f = sender as ShapedForm;
            Screen myScreen = Screen.FromControl(this);
            Rectangle area = myScreen.WorkingArea;
            if (f.Left + f.Width > area.Width)
            {
                f.Left = area.Width - f.Width -5;
            }
        }