private class DataGridViewAllocationCell : DataGridViewButtonCell
        {
            public void Initialize(ReleaseSetupData releaseSetupData, string initialFieldName = NOTHING_SELECTED_TEXT, AllocationFieldType initialFieldType = AllocationFieldType.None)
            {
                FieldName = initialFieldName;
                FieldType = initialFieldType;

                contextMenu = new ContextMenuStrip();

                ToolStripMenuItem clearSelectionItem = RegisterMenuItem(NOTHING_SELECTED_TEXT);
                clearSelectionItem.Click += (object sender, EventArgs e) => MenuItem_OnClick(sender, e, NOTHING_SELECTED_TEXT, AllocationFieldType.None);

                contextMenu.Items.Add(new ToolStripSeparator());

                ToolStripMenuItem menuItemIndexField = RegisterMenuItem("Indexfelder");
                foreach (IndexField field in releaseSetupData.IndexFields)
                {
                    RegisterSubMenuItem(menuItemIndexField, field.Name, AllocationFieldType.IndexField);
                }

                ToolStripMenuItem menuItemBatchField = RegisterMenuItem("Batchfelder");
                foreach (BatchField field in releaseSetupData.BatchFields)
                {
                    RegisterSubMenuItem(menuItemBatchField, field.Name, AllocationFieldType.BatchField);
                }

                ToolStripMenuItem menuItemKofaxValue = RegisterMenuItem("KofaxValues");
                foreach (dynamic field in releaseSetupData.BatchVariableNames)
                {
                    RegisterSubMenuItem(menuItemKofaxValue, field, AllocationFieldType.KofaxValue);
                }
            }

            private ContextMenuStrip contextMenu;

            private const string BUTTON_TEXT = "...";
            private const string NOTHING_SELECTED_TEXT = "[ Kein Eintrag ]";

            public string FieldName { get; private set; }
            public AllocationFieldType FieldType { get; private set; }

            private DataGridViewAllocationColumn ParentColumn { get { return OwningColumn as DataGridViewAllocationColumn; } }

            private int LabelWidth { get { return TextRenderer.MeasureText(FieldName, ParentColumn.DefaultCellStyle.Font).Width; } }

            private ToolStripMenuItem RegisterMenuItem(string itemName)
            {
                return contextMenu.Items.Add(itemName) as ToolStripMenuItem;
            }

            private void RegisterSubMenuItem(ToolStripMenuItem menuItem, string fieldName, AllocationFieldType fieldType)
            {
                menuItem.DropDownItems.Add(fieldName, null, (object sender, EventArgs e) => MenuItem_OnClick(sender, e, fieldName, fieldType));
            }

            private void MenuItem_OnClick(object sender, EventArgs e, string fieldName, AllocationFieldType fieldType)
            {
                FieldName = fieldName;
                FieldType = fieldType;
                DataGridView.Refresh();
            }

            protected override void Paint(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, int rowIndex, DataGridViewElementStates elementState, object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
            {
                base.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, DataGridViewPaintParts.All & ~DataGridViewPaintParts.ContentBackground & ~DataGridViewPaintParts.ContentForeground);
                Rectangle displayRectangle = DataGridView.GetCellDisplayRectangle(ParentColumn.Index, rowIndex, false);
                Rectangle cellRectangle = GetContentBounds(rowIndex);
                Rectangle labelRectangle = new Rectangle(displayRectangle.Location, new Size(LabelWidth, displayRectangle.Height));
                cellRectangle.Offset(displayRectangle.Location);
                base.Paint(graphics, clipBounds, cellRectangle, rowIndex, elementState, value, BUTTON_TEXT, errorText, cellStyle, advancedBorderStyle, DataGridViewPaintParts.All);
                TextRenderer.DrawText(graphics, FieldName, cellStyle.Font, labelRectangle, cellStyle.ForeColor);
            }

            protected override Rectangle GetContentBounds(Graphics graphics, DataGridViewCellStyle cellStyle, int rowIndex)
            {
                Rectangle rectangle = base.GetContentBounds(graphics, cellStyle, rowIndex);
                return new Rectangle(rectangle.Width - rectangle.Height, rectangle.Top, rectangle.Height, rectangle.Height);
            }

            protected override void OnContentClick(DataGridViewCellEventArgs e)
            {
                base.OnContentClick(e);
                Rectangle contentRectangle = GetContentBounds(e.RowIndex);
                Rectangle displayRectangle = DataGridView.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, false);
                Point location = new Point(displayRectangle.Left + contentRectangle.Left, displayRectangle.Top + contentRectangle.Bottom);
                contextMenu.Show(DataGridView, location);
            }
        }