/// <summary>
        /// Reorganises the positions of all the text boxes in the beam.
        /// </summary>
        private static void ReorganiseBeam(PowerPointSlide refSlide, List<AgendaSection> newSections, Shape highlightedTextBox,
            Shape background, BeamFormats beamFormats, List<Shape> oldTextBoxes, Shape beamShape)
        {
            var newTextBoxes = CreateBeamAgendaTextBoxes(refSlide, newSections);
            SetupBeamTextBoxPositions(newTextBoxes, highlightedTextBox, background);

            for (int i = 0; i < newTextBoxes.Count; ++i)
            {
                var referenceTextFormat = beamFormats.Regular;
                if (i < oldTextBoxes.Count) referenceTextFormat = oldTextBoxes[i].TextFrame2.TextRange;

                Graphics.SyncTextRange(referenceTextFormat, newTextBoxes[i].TextFrame2.TextRange, pickupTextContent: false);
            }

            oldTextBoxes.ForEach(shape => shape.Delete());

            var beamShapeShapes = beamShape.Ungroup().Cast<Shape>().ToList();
            beamShapeShapes.AddRange(newTextBoxes);
            beamShape = refSlide.GroupShapes(beamShapeShapes);
            AgendaShape.SetShapeName(beamShape, ShapePurpose.BeamShapeMainGroup, AgendaSection.None);
        }
        /// <summary>
        /// Does not reogranise the positions of the text boxes in the beam. Instead, it only deletes text boxes
        /// that no longer correspond to a section, and creates new text boxes for the new sections.
        /// </summary>
        private static void UpdateBeamItems(PowerPointSlide refSlide, List<AgendaSection> newSections, Shape highlightedTextBox,
                Shape background, BeamFormats beamFormats, List<Shape> oldTextBoxes, Shape beamShape)
        {
            List<Shape> markedForDeletion;
            var textboxAssignment = GetBeamTextboxAssignment(oldTextBoxes, out markedForDeletion);

            var reassignedTextboxIndexes = new HashSet<int>();
            var newTextboxes = new List<Shape>();

            foreach (var section in newSections)
            {
                int index = section.Index;
                if (textboxAssignment.ContainsKey(index))
                {
                    // Reuse old textbox
                    var textbox = textboxAssignment[index];
                    Graphics.SetText(textbox, section.Name);
                    AgendaShape.SetShapeName(textbox, ShapePurpose.BeamShapeText, section);
                    reassignedTextboxIndexes.Add(index);
                }
                else
                {
                    // Create new textbox
                    var textbox = PrepareBeamAgendaBeamItem(refSlide, section);
                    var referenceTextFormat = beamFormats.Regular;
                    Graphics.SyncTextRange(referenceTextFormat, textbox.TextFrame2.TextRange, pickupTextContent: false);
                    newTextboxes.Add(textbox);
                }
            }
            
            markedForDeletion.AddRange(from entry in textboxAssignment where !reassignedTextboxIndexes.Contains(entry.Key) select entry.Value);
            markedForDeletion.ForEach(shape => shape.Delete());

            var beamShapeShapes = beamShape.Ungroup().Cast<Shape>().ToList();
            beamShapeShapes.AddRange(newTextboxes);
            beamShape = refSlide.GroupShapes(beamShapeShapes);
            AgendaShape.SetShapeName(beamShape, ShapePurpose.BeamShapeMainGroup, AgendaSection.None);
        }
        private static void CreateBeamAgendaShapes(PowerPointSlide refSlide, Direction beamDirection = Direction.Top)
        {
            var sections = GetAllButFirstSection();

            var background = PrepareBeamAgendaBackground(refSlide);
            var textBoxes = CreateBeamAgendaTextBoxes(refSlide, sections);
            var highlightedTextBox = CreateHighlightedTextBox(refSlide);
            SetupBeamTextBoxPositions(textBoxes, highlightedTextBox, background);
            MatchColour(highlightedTextBox, background);

            var beamShapeItems = new List<Shape>();
            beamShapeItems.Add(background);
            beamShapeItems.Add(highlightedTextBox);
            beamShapeItems.AddRange(textBoxes);

            var group = refSlide.GroupShapes(beamShapeItems);
            AgendaShape.SetShapeName(group, ShapePurpose.BeamShapeMainGroup, AgendaSection.None);
        }