diff --git a/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj b/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj
index d6d0784..94f3964 100644
--- a/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj
+++ b/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj
@@ -132,6 +132,8 @@
   <ItemGroup>
     <Compile Include="Excel\CalcEngine\Functions\DateAndTime.cs" />
     <Compile Include="Excel\CalcEngine\Functions\Database.cs" />
+    <Compile Include="Excel\Misc\XLCallbackAction.cs" />
+    <Compile Include="Excel\Misc\XLReentrantEnumerableSet.cs" />
     <Compile Include="XLHelper.cs" />
     <Compile Include="Excel\AutoFilters\XLFilteredColumn.cs" />
     <Compile Include="Excel\AutoFilters\XLCustomFilteredColumn.cs" />
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Columns/XLColumn.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Columns/XLColumn.cs
index 2a909b4..e75111a 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Columns/XLColumn.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Columns/XLColumn.cs
@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Drawing;
 
+
 namespace ClosedXML.Excel
 {
     internal class XLColumn : XLRangeBase, IXLColumn
@@ -29,7 +30,7 @@
 
             IsReference = xlColumnParameters.IsReference;
             if (IsReference)
-                SubscribeToShiftedColumns(WorksheetRangeShiftedColumns);
+                SubscribeToShiftedColumns((range, columnsShifted) => this.WorksheetRangeShiftedColumns(range, columnsShifted));
             else
             {
                 SetStyle(xlColumnParameters.DefaultStyleId);
@@ -46,8 +47,8 @@
             _width = column._width;
             IsReference = column.IsReference;
             if (IsReference)
-                SubscribeToShiftedColumns(WorksheetRangeShiftedColumns);
-            _collapsed = column._collapsed;
+				SubscribeToShiftedColumns((range, columnsShifted) => this.WorksheetRangeShiftedColumns(range, columnsShifted));
+			_collapsed = column._collapsed;
             _isHidden = column._isHidden;
             _outlineLevel = column._outlineLevel;
             SetStyle(column.GetStyleId());
@@ -215,7 +216,7 @@
             {
                 using (var asRange = column.AsRange())
                 {
-                    asRange.InsertColumnsAfter(true, numberOfColumns).Dispose();
+                    asRange.InsertColumnsAfterVoid(true, numberOfColumns);
                 }
             }
 
@@ -241,7 +242,7 @@
             {
                 using (var asRange = column.AsRange())
                 {
-                    asRange.InsertColumnsBefore(true, numberOfColumns).Dispose();
+                    asRange.InsertColumnsBeforeVoid(true, numberOfColumns);
                 }
             }
 
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Misc/XLCallbackAction.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Misc/XLCallbackAction.cs
new file mode 100644
index 0000000..9238200
--- /dev/null
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Misc/XLCallbackAction.cs
@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace ClosedXML.Excel.Misc
+{
+	internal class XLCallbackAction
+	{
+		public XLCallbackAction(Action<XLRange, Int32> action)
+		{
+			this.Action = action;
+		}
+
+		public Action<XLRange, Int32> Action { get; set; }
+	}
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Misc/XLReentrantEnumerableSet.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Misc/XLReentrantEnumerableSet.cs
new file mode 100644
index 0000000..c902733
--- /dev/null
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Misc/XLReentrantEnumerableSet.cs
@@ -0,0 +1,100 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Collections;
+
+namespace ClosedXML.Excel.Misc
+{
+	/// <summary>
+	/// This is most definitely NOT thread-safe, but it is reentrant (e.g. you can insert and remove
+	/// items during enumeration)
+	/// </summary>
+	/// <typeparam name="T"></typeparam>
+	internal class XLReentrantEnumerableSet<T> : IEnumerable<T>
+	{
+		private HashSet<T> _hashSet;
+		private List<T> _list;
+
+		private int _activeEnumerators;
+
+		public XLReentrantEnumerableSet()
+		{
+			_list = new List<T>();
+			_hashSet = new HashSet<T>();
+		}
+
+		public void Add(T item)
+		{
+			if(!_hashSet.Contains(item))
+			{
+				// Add item to end of list
+				_list.Add(item);
+
+				// Store the item in the hashset too.
+				_hashSet.Add(item);
+			}
+		}
+
+		public void Remove(T item)
+		{
+			_hashSet.Remove(item);
+			
+			fixup();
+		}
+
+		private void fixup()
+		{
+			// Only fixup the list if there are no active enumerators
+			if(_activeEnumerators > 0)
+				return;
+
+			// Only fixup the list if there are more than a certain number of items to deal with
+			// This saves fixing up the list continually.
+			if(_list.Count < 1000 || (_list.Count < _hashSet.Count * 1.5))
+				return;
+
+			// Rebuild the list skipping out omitted items
+			_list = _list.Where(item => _hashSet.Contains(item)).ToList();
+		}
+		
+		public IEnumerator<T> GetEnumerator()
+		{
+			// Mark that we are enumerating
+			_activeEnumerators++;
+			try
+			{
+				int idx = 0;
+
+				// Important, store count here, as more items may be added while we are enumerating
+				// and we only want to enumerate items that were already there.
+				int count = _list.Count;
+				while(idx < count)
+				{
+					var item = _list[idx];
+
+					// Skip over items in the list which aren't in the hashset; they could have been
+					// removed while we were enumerating or previously removed.
+					if(_hashSet.Contains(item))
+					{
+						yield return item;
+					}
+
+					idx++;
+				}
+
+			}
+			finally
+			{
+				// Finished enumerating, can now fixup
+				_activeEnumerators--;
+				fixup();
+			}
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return this.GetEnumerator();
+		}
+	}
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRange.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRange.cs
index 73bd719..6ffdff1 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRange.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRange.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 
+
 namespace ClosedXML.Excel
 {
     internal class XLRange : XLRangeBase, IXLRange
@@ -15,8 +16,8 @@
 
             if (!xlRangeParameters.IgnoreEvents)
             {
-                SubscribeToShiftedRows(WorksheetRangeShiftedRows);
-                SubscribeToShiftedColumns(WorksheetRangeShiftedColumns);
+                SubscribeToShiftedRows((range, rowShifted) => this.WorksheetRangeShiftedRows(range, rowShifted));
+                SubscribeToShiftedColumns((range, columnsShifted) => this.WorksheetRangeShiftedColumns(range, columnsShifted));
                 //xlRangeParameters.IgnoreEvents = true;
             }
             SetStyle(xlRangeParameters.DefaultStyle);
@@ -806,4 +807,4 @@
             return this;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs
index 914e55b..f9ab78d 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs
@@ -1,8 +1,10 @@
-using System;
+using ClosedXML.Excel.Misc;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
 
+
 namespace ClosedXML.Excel
 {
     internal abstract class XLRangeBase : IXLRangeBase, IXLStylized
@@ -55,25 +57,26 @@
         }
 
         #endregion
-        
-        private Boolean _subscribedToShiftedRows;
-        protected void SubscribeToShiftedRows(RangeShiftedRowsDelegate worksheetRangeShiftedRows)
+
+		private XLCallbackAction _shiftedRowsAction;
+
+        protected void SubscribeToShiftedRows(Action<XLRange, Int32> action)
         {
             if (Worksheet == null || !Worksheet.EventTrackingEnabled) return;
 
-            WorksheetRangeShiftedRows = worksheetRangeShiftedRows;
-            RangeAddress.Worksheet.RangeShiftedRows += WorksheetRangeShiftedRows;
-            _subscribedToShiftedRows = true;
+			_shiftedRowsAction = new XLCallbackAction(action);
+
+			RangeAddress.Worksheet.RangeShiftedRows.Add(_shiftedRowsAction);
         }
 
-        private Boolean _subscribedToShiftedColumns;
-        protected void SubscribeToShiftedColumns(RangeShiftedColumnsDelegate worksheetRangeShiftedColumns)
+        private XLCallbackAction _shiftedColumnsAction;
+		protected void SubscribeToShiftedColumns(Action<XLRange, Int32> action)
         {
             if (Worksheet == null || !Worksheet.EventTrackingEnabled) return;
 
-            WorksheetRangeShiftedColumns = worksheetRangeShiftedColumns;
-            RangeAddress.Worksheet.RangeShiftedColumns += WorksheetRangeShiftedColumns;
-            _subscribedToShiftedColumns = true;
+            _shiftedColumnsAction = new XLCallbackAction(action);
+
+			RangeAddress.Worksheet.RangeShiftedColumns.Add(_shiftedColumnsAction);
         }
 
         #region Public properties
@@ -947,6 +950,16 @@
         }
 
         public IXLRangeColumns InsertColumnsAfter(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true)
+		{
+			return InsertColumnsAfterInternal(onlyUsedCells, numberOfColumns, formatFromLeft);
+		}
+
+		public void InsertColumnsAfterVoid(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true)
+		{
+			InsertColumnsAfterInternal(onlyUsedCells, numberOfColumns, formatFromLeft, nullReturn: true);
+		}
+
+        private IXLRangeColumns InsertColumnsAfterInternal(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true, Boolean nullReturn = false)
         {
             int columnCount = ColumnCount();
             int firstColumn = RangeAddress.FirstAddress.ColumnNumber + columnCount;
@@ -962,7 +975,7 @@
                 lastRow = XLHelper.MaxRowNumber;
 
             var newRange = Worksheet.Range(firstRow, firstColumn, lastRow, lastColumn);
-            return newRange.InsertColumnsBefore(onlyUsedCells, numberOfColumns, formatFromLeft);
+            return newRange.InsertColumnsBeforeInternal(onlyUsedCells, numberOfColumns, formatFromLeft, nullReturn);
         }
 
         public IXLRangeColumns InsertColumnsBefore(Int32 numberOfColumns)
@@ -991,7 +1004,17 @@
             return retVal;
         }
 
-        public IXLRangeColumns InsertColumnsBefore(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true)
+		public IXLRangeColumns InsertColumnsBefore(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true)
+		{
+			return InsertColumnsBeforeInternal(onlyUsedCells, numberOfColumns, formatFromLeft);
+		}
+
+		public void InsertColumnsBeforeVoid(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true)
+		{
+			InsertColumnsBeforeInternal(onlyUsedCells, numberOfColumns, formatFromLeft, nullReturn: true);
+		}
+
+        private IXLRangeColumns InsertColumnsBeforeInternal(Boolean onlyUsedCells, Int32 numberOfColumns, Boolean formatFromLeft = true, Boolean nullReturn = false)
         {
             foreach (XLWorksheet ws in Worksheet.Workbook.WorksheetsInternal)
             {
@@ -1120,6 +1143,8 @@
                 }
             }
 
+			if(nullReturn)
+				return null;
             
             return rangeToReturn.Columns();
         }
@@ -1150,8 +1175,18 @@
             return retVal;
         }
 
-        public IXLRangeRows InsertRowsBelow(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove = true)
-        {
+		public IXLRangeRows InsertRowsBelow(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove = true)
+		{
+			return InsertRowsBelowInternal(onlyUsedCells, numberOfRows, formatFromAbove, nullReturn: false);
+		}
+
+		public void InsertRowsBelowVoid(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove = true)
+		{
+			InsertRowsBelowInternal(onlyUsedCells, numberOfRows, formatFromAbove, nullReturn: true);
+		}
+
+		private IXLRangeRows InsertRowsBelowInternal(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove, Boolean nullReturn)
+		{
             int rowCount = RowCount();
             int firstRow = RangeAddress.FirstAddress.RowNumber + rowCount;
             if (firstRow > XLHelper.MaxRowNumber)
@@ -1166,7 +1201,7 @@
                 lastColumn = XLHelper.MaxColumnNumber;
 
             var newRange = Worksheet.Range(firstRow, firstColumn, lastRow, lastColumn);
-            return newRange.InsertRowsAbove(onlyUsedCells, numberOfRows, formatFromAbove);
+            return newRange.InsertRowsAboveInternal(onlyUsedCells, numberOfRows, formatFromAbove, nullReturn);
         }
 
         public IXLRangeRows InsertRowsAbove(Int32 numberOfRows)
@@ -1200,8 +1235,17 @@
             public XLAddress SourceAddress;
             public XLDataValidation DataValidation;
         }
-        public IXLRangeRows InsertRowsAbove(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove = true)
-        {
+		public void InsertRowsAboveVoid(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove = true)
+		{
+			InsertRowsAboveInternal(onlyUsedCells, numberOfRows, formatFromAbove, nullReturn: true);
+		}
+		public IXLRangeRows InsertRowsAbove(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove = true)
+		{
+			return InsertRowsAboveInternal(onlyUsedCells, numberOfRows, formatFromAbove, nullReturn: false);
+		}
+
+		private IXLRangeRows InsertRowsAboveInternal(Boolean onlyUsedCells, Int32 numberOfRows, Boolean formatFromAbove, Boolean nullReturn)
+		{
             using (var asRange = AsRange())
                 foreach (XLWorksheet ws in Worksheet.Workbook.WorksheetsInternal)
                 {
@@ -1330,6 +1374,10 @@
                 }
             }
 
+			// Skip calling .Rows() for performance reasons if required.
+			if(nullReturn)
+				return null;
+
             return rangeToReturn.Rows();
         }
 
@@ -1882,23 +1930,19 @@
                 new XLRangeParameters(new XLRangeAddress(firstCellAddress, lastCellAddress), Worksheet.Style), true);
         }
 
-        private RangeShiftedRowsDelegate WorksheetRangeShiftedRows;
-        
-        private RangeShiftedColumnsDelegate WorksheetRangeShiftedColumns;
-        
-
         public void Dispose()
         {
-            if (_subscribedToShiftedRows)
+			if(_shiftedRowsAction != null)
             {
-                RangeAddress.Worksheet.RangeShiftedRows -= WorksheetRangeShiftedRows;
-                _subscribedToShiftedRows = false;
+                RangeAddress.Worksheet.RangeShiftedRows.Remove(_shiftedRowsAction);
+				_shiftedRowsAction = null;
             }
 
-            if (!_subscribedToShiftedColumns) return;
-
-            RangeAddress.Worksheet.RangeShiftedColumns -= WorksheetRangeShiftedColumns;
-            _subscribedToShiftedColumns = false;
+			if(_shiftedColumnsAction != null)
+			{
+				RangeAddress.Worksheet.RangeShiftedColumns.Remove(_shiftedColumnsAction);
+				_shiftedColumnsAction = null;
+			}
         }
 
         public IXLDataValidation SetDataValidation()
@@ -1933,4 +1977,4 @@
             Worksheet.SelectedRanges.Add(AsRange());
         }
     }
-}
\ No newline at end of file
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeColumn.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeColumn.cs
index 3ecd2fe..77fc1ba 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeColumn.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeColumn.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Linq;
+	
 
     internal class XLRangeColumn : XLRangeBase, IXLRangeColumn
     {
@@ -12,8 +13,8 @@
         {
             if (quickLoad) return;
 
-            SubscribeToShiftedRows((range, rowsShifted) => WorksheetRangeShiftedRows(range, rowsShifted));
-            SubscribeToShiftedColumns((range, columnsShifted) => WorksheetRangeShiftedColumns(range, columnsShifted));
+			SubscribeToShiftedRows((range, rowsShifted) => this.WorksheetRangeShiftedRows(range, rowsShifted));
+			SubscribeToShiftedColumns((range, columnsShifted) => this.WorksheetRangeShiftedColumns(range, columnsShifted));
             SetStyle(rangeParameters.DefaultStyle);
         }
 
@@ -351,4 +352,4 @@
         }
 
     }
-}
\ No newline at end of file
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeRow.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeRow.cs
index 7aab510..802342f 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeRow.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeRow.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Linq;
+	
 
     internal class XLRangeRow : XLRangeBase, IXLRangeRow
     {
@@ -14,8 +15,8 @@
             if (quickLoad) return;
             if (!RangeParameters.IgnoreEvents)
             {
-                SubscribeToShiftedRows((range, rowsShifted) => WorksheetRangeShiftedRows(range, rowsShifted));
-                SubscribeToShiftedColumns((range, columnsShifted) => WorksheetRangeShiftedColumns(range, columnsShifted));
+                SubscribeToShiftedRows((range, rowsShifted) => this.WorksheetRangeShiftedRows(range, rowsShifted));
+                SubscribeToShiftedColumns((range, columnsShifted) => this.WorksheetRangeShiftedColumns(range, columnsShifted));
             }
             SetStyle(rangeParameters.DefaultStyle);
         }
@@ -273,11 +274,17 @@
         private XLRangeRow RowShift(Int32 rowsToShift)
         {
             Int32 rowNum = RowNumber() + rowsToShift;
-            return Worksheet.Range(
+
+            var range = Worksheet.Range(
                 rowNum,
                 RangeAddress.FirstAddress.ColumnNumber,
                 rowNum,
-                RangeAddress.LastAddress.ColumnNumber).FirstRow();
+                RangeAddress.LastAddress.ColumnNumber);
+                
+            var result = range.FirstRow();
+            range.Dispose();
+
+            return result;
         }
 
         #region XLRangeRow Above
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Rows/XLRow.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Rows/XLRow.cs
index 806a23c..f9772e6 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Rows/XLRow.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Rows/XLRow.cs
@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Drawing;
 
+
 namespace ClosedXML.Excel
 {
     internal class XLRow : XLRangeBase, IXLRow
@@ -27,7 +28,7 @@
 
             IsReference = xlRowParameters.IsReference;
             if (IsReference)
-                SubscribeToShiftedRows(WorksheetRangeShiftedRows);
+                SubscribeToShiftedRows((range, rowShifted) => this.WorksheetRangeShiftedRows(range, rowShifted));
             else
             {
                 SetStyle(xlRowParameters.DefaultStyleId);
@@ -43,7 +44,7 @@
             _height = row._height;
             IsReference = row.IsReference;
             if (IsReference)
-                SubscribeToShiftedRows(WorksheetRangeShiftedRows);
+				SubscribeToShiftedRows((range, rowShifted) => this.WorksheetRangeShiftedRows(range, rowShifted));
 
             _collapsed = row._collapsed;
             _isHidden = row._isHidden;
@@ -159,7 +160,7 @@
             {
                 using (var asRange = row.AsRange())
                 {
-                    asRange.InsertRowsBelow(true, numberOfRows).Dispose();
+                    asRange.InsertRowsBelowVoid(true, numberOfRows);
                 }
             }
             var newRows = Worksheet.Rows(rowNum + 1, rowNum + numberOfRows);
@@ -198,7 +199,7 @@
             {
                 using (var asRange = row.AsRange())
                 {
-                    asRange.InsertRowsAbove(true, numberOfRows).Dispose();
+                    asRange.InsertRowsAboveVoid(true, numberOfRows);
                 }
             }
 
@@ -703,4 +704,4 @@
 
         
     }
-}
\ No newline at end of file
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs
index 0a7be5c..8b447b2 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs
@@ -4,13 +4,11 @@
 using System.Text;
 using System.Text.RegularExpressions;
 using ClosedXML.Excel.CalcEngine;
+using ClosedXML.Excel.Misc;
+
 
 namespace ClosedXML.Excel
 {
-    internal delegate void RangeShiftedRowsDelegate(XLRange range, Int32 rowsShifted);
-
-    internal delegate void RangeShiftedColumnsDelegate(XLRange range, Int32 columnsShifted);
-
     internal class XLWorksheet : XLRangeBase, IXLWorksheet
     {
         #region Constants
@@ -19,8 +17,8 @@
 
         #region Events
 
-        public event RangeShiftedRowsDelegate RangeShiftedRows;
-        public event RangeShiftedColumnsDelegate RangeShiftedColumns;
+		public XLReentrantEnumerableSet<XLCallbackAction> RangeShiftedRows;
+		public XLReentrantEnumerableSet<XLCallbackAction> RangeShiftedColumns;
 
         #endregion
 
@@ -46,6 +44,10 @@
                     new XLAddress(null, XLHelper.MaxRowNumber, XLHelper.MaxColumnNumber, false, false)))
         {
             EventTrackingEnabled = workbook.EventTracking == XLEventTracking.Enabled;
+
+			RangeShiftedRows = new XLReentrantEnumerableSet<XLCallbackAction>();
+			RangeShiftedColumns = new XLReentrantEnumerableSet<XLCallbackAction>();
+
             RangeAddress.Worksheet = this;
             RangeAddress.FirstAddress.Worksheet = this;
             RangeAddress.LastAddress.Worksheet = this;
@@ -68,9 +70,9 @@
             _columnWidth = workbook.ColumnWidth;
             _rowHeight = workbook.RowHeight;
             RowHeightChanged = Math.Abs(workbook.RowHeight - XLWorkbook.DefaultRowHeight) > XLHelper.Epsilon;
-            Name = sheetName;
-            SubscribeToShiftedRows(WorksheetRangeShiftedRows);
-            SubscribeToShiftedColumns(WorksheetRangeShiftedColumns);
+			Name = sheetName;
+			SubscribeToShiftedRows((range, rowsShifted) => this.WorksheetRangeShiftedRows(range, rowsShifted));
+			SubscribeToShiftedColumns((range, columnsShifted) => this.WorksheetRangeShiftedColumns(range, columnsShifted));
             Charts = new XLCharts();
             ShowFormulas = workbook.ShowFormulas;
             ShowGridLines = workbook.ShowGridLines;
@@ -1318,13 +1320,23 @@
         public void NotifyRangeShiftedRows(XLRange range, Int32 rowsShifted)
         {
             if (RangeShiftedRows != null)
-                RangeShiftedRows(range, rowsShifted);
+            {
+                foreach(var item in RangeShiftedRows)
+                {
+                    item.Action(range, rowsShifted);
+                }
+            }
         }
 
         public void NotifyRangeShiftedColumns(XLRange range, Int32 columnsShifted)
         {
             if (RangeShiftedColumns != null)
-                RangeShiftedColumns(range, columnsShifted);
+            {
+                foreach(var item in RangeShiftedColumns)
+                {
+                    item.Action(range, columnsShifted);
+                }
+            }
         }
 
         public XLRow Row(Int32 row, Boolean pingCells)
diff --git a/ClosedXML/ClosedXML/ClosedXML_Net3.5/ClosedXML_Net3.5.csproj b/ClosedXML/ClosedXML/ClosedXML_Net3.5/ClosedXML_Net3.5.csproj
index 8da1ad5..4fbd00f 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Net3.5/ClosedXML_Net3.5.csproj
+++ b/ClosedXML/ClosedXML/ClosedXML_Net3.5/ClosedXML_Net3.5.csproj
@@ -510,6 +510,9 @@
     <Compile Include="..\ClosedXML\Excel\IXLWorksheets.cs">
       <Link>Excel\IXLWorksheets.cs</Link>
     </Compile>
+    <Compile Include="..\ClosedXML\Excel\Misc\XLCallbackAction.cs">
+      <Link>Excel\Misc\XLCallbackAction.cs</Link>
+    </Compile>
     <Compile Include="..\ClosedXML\Excel\Misc\XLDictionary.cs">
       <Link>Excel\Misc\XLDictionary.cs</Link>
     </Compile>
@@ -519,6 +522,9 @@
     <Compile Include="..\ClosedXML\Excel\Misc\XLIdManager.cs">
       <Link>Excel\Misc\XLIdManager.cs</Link>
     </Compile>
+    <Compile Include="..\ClosedXML\Excel\Misc\XLReentrantEnumerableSet.cs">
+      <Link>Excel\Misc\XLReentrantEnumerableSet.cs</Link>
+    </Compile>
     <Compile Include="..\ClosedXML\Excel\NamedRanges\IXLNamedRange.cs">
       <Link>Excel\NamedRanges\IXLNamedRange.cs</Link>
     </Compile>
diff --git a/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs b/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
index 9e2bb7b..46b1c77 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
+++ b/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
@@ -12,7 +12,19 @@
     {
         static void Main(string[] args)
         {
+            var wb = new XLWorkbook();
+            
+            foreach (var wsNum in Enumerable.Range(1, 5))
+            {
+                var ws = wb.AddWorksheet(wsNum.ToString());
+                var rowNum = Math.Pow(10, wsNum);
+                var start = DateTime.Now;
+                ws.FirstRow().InsertRowsBelow((int)rowNum);
+                var end = DateTime.Now;
 
+                Console.WriteLine(rowNum + " rows in " + (end - start).TotalSeconds + " seconds.");
+            }
+            Console.ReadKey();
         }
     }
 
diff --git a/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Misc/WorkbookProperties.xlsx b/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Misc/WorkbookProperties.xlsx
index 6007842..da39cda 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Misc/WorkbookProperties.xlsx
+++ b/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Misc/WorkbookProperties.xlsx
Binary files differ
diff --git a/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Styles/UsingRichText.xlsx b/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Styles/UsingRichText.xlsx
index 18fff6e..cfc3637 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Styles/UsingRichText.xlsx
+++ b/ClosedXML/ClosedXML/ClosedXML_Tests/Resource/Examples/Styles/UsingRichText.xlsx
Binary files differ
diff --git a/ClosedXML/ClosedXML/ClosedXML_Tests/TestHelper.cs b/ClosedXML/ClosedXML/ClosedXML_Tests/TestHelper.cs
index 50fddbf..35fde24 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Tests/TestHelper.cs
+++ b/ClosedXML/ClosedXML/ClosedXML_Tests/TestHelper.cs
@@ -19,7 +19,13 @@
         //Note: Run example tests parameters
         public static string TestsOutputDirectory
         {
-            get { return Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location); }
+            get { 
+                var preferredPath = "C:\\ClosedXML_Tests";
+                if (Directory.Exists(preferredPath))
+                    return preferredPath; 
+
+                return Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location); 
+            }
 
         }