diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs
index 62cb520..11eb172 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/AutoFilters/XLFilterColumn.cs
@@ -185,8 +185,9 @@
             _autoFilter.Filters.Add(_column, new List<XLFilter>());
 
             Boolean addToList = true;
-            using (var rows = _autoFilter.Range.Rows(2, _autoFilter.Range.RowCount()))
-            {
+            var ws = _autoFilter.Range.Worksheet as XLWorksheet;
+            ws.SuspendEvents();
+            var rows = _autoFilter.Range.Rows(2, _autoFilter.Range.RowCount());
                 foreach (IXLRangeRow row in rows)
                 {
                     Boolean foundOne = false;
@@ -206,15 +207,15 @@
 
                         var cell = row.Cell(_column);
                         if (cell.DataType != XLCellValues.Number || !condition(cell.GetDouble())) continue;
-                        row.WorksheetRow().Unhide().Dispose();
+                        row.WorksheetRow().Unhide();
                         foundOne = true;
                     }
                     if (!foundOne)
-                        row.WorksheetRow().Hide().Dispose();
+                        row.WorksheetRow().Hide();
 
                     addToList = false;
                 }
-            }
+            ws.ResumeEvents();
         }
 
         private IEnumerable<double> GetValues(int value, XLTopBottomType type, bool takeTop)
@@ -261,8 +262,10 @@
             _autoFilter.Filters.Add(_column, new List<XLFilter>());
 
             Boolean addToList = true;
-            using (var rows = _autoFilter.Range.Rows(2, _autoFilter.Range.RowCount()))
-            {
+            var ws = _autoFilter.Range.Worksheet as XLWorksheet;
+            ws.SuspendEvents();
+            var rows = _autoFilter.Range.Rows(2, _autoFilter.Range.RowCount());
+            
                 foreach (IXLRangeRow row in rows)
                 {
                     Boolean foundOne = false;
@@ -282,16 +285,17 @@
 
                         var cell = row.Cell(_column);
                         if (cell.DataType != XLCellValues.Number || !condition(cell.GetDouble())) continue;
-                        row.WorksheetRow().Unhide().Dispose();
+                        row.WorksheetRow().Unhide();
                         foundOne = true;
                     }
 
                     if (!foundOne)
-                        row.WorksheetRow().Hide().Dispose();
+                        row.WorksheetRow().Hide();
 
                     addToList = false;
                 }
-            }
+            
+            ws.ResumeEvents();
         }
 
         private IEnumerable<double> GetAverageValues(bool aboveAverage)
@@ -360,20 +364,21 @@
             }
             _autoFilter.Column(_column).FilterType = filterType;
             Boolean isText = typeof(T) == typeof(String);
-            using (var rows = _autoFilter.Range.Rows(2, _autoFilter.Range.RowCount()))
+            var ws = _autoFilter.Range.Worksheet as XLWorksheet;
+            ws.SuspendEvents();
+            var rows = _autoFilter.Range.Rows(2, _autoFilter.Range.RowCount());
+            foreach (IXLRangeRow row in rows)
             {
-                foreach (IXLRangeRow row in rows)
-                {
-                    Boolean match = isText
-                                        ? condition(row.Cell(_column).GetString())
-                                        : row.Cell(_column).DataType == XLCellValues.Number &&
-                                          condition(row.Cell(_column).GetDouble());
-                    if (match)
-                        row.WorksheetRow().Unhide().Dispose();
-                    else
-                        row.WorksheetRow().Hide().Dispose();
-                }
+                Boolean match = isText
+                                    ? condition(row.Cell(_column).GetString())
+                                    : row.Cell(_column).DataType == XLCellValues.Number &&
+                                        condition(row.Cell(_column).GetDouble());
+                if (match)
+                    row.WorksheetRow().Unhide();
+                else
+                    row.WorksheetRow().Hide();
             }
+            ws.ResumeEvents();
             return new XLFilterConnector(_autoFilter, _column);
         }
 
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook.cs
index f7a65b6..52b3e3e 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Security.AccessControl;
 
 namespace ClosedXML.Excel
 {
@@ -428,7 +429,7 @@
                 CreatePackage(stream, true);
             else if (_loadSource == XLLoadSource.File)
             {
-                using (var fileStream = new FileStream(_originalFile, FileMode.Open))
+                using (var fileStream = new FileStream(_originalFile, FileMode.Open, FileAccess.Read))
                 {
                     CopyStream(fileStream, stream);
                     fileStream.Close();
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs
index fb6c974..4748be5 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorksheet.cs
@@ -1370,5 +1370,25 @@
         public IXLRanges MergedRanges { get { return Internals.MergedRanges; } }
 
         public IXLConditionalFormats ConditionalFormats { get; private set; }
+
+        private Boolean _eventTracking;
+        public void SuspendEvents()
+        {
+            _eventTracking = EventTrackingEnabled;
+            EventTrackingEnabled = false;
+        }
+        public void ResumeEvents()
+        {
+            EventTrackingEnabled = _eventTracking;
+        }
+        //public new Int32 RowCount()
+        //{
+        //    return XLHelper.MaxRowNumber;
+        //}
+
+        //public new Int32 ColumnCount()
+        //{
+        //    return XLHelper.MaxColumnNumber;
+        //}
     }
 }
\ No newline at end of file
diff --git a/ClosedXML/ClosedXML/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs b/ClosedXML/ClosedXML/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs
index d3ff18b..cefe55c 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs
+++ b/ClosedXML/ClosedXML/ClosedXML_Tests/Excel/Worksheets/XLWorksheetTests.cs
@@ -76,6 +76,27 @@
             Assert.AreEqual("Sheet2", wb.Worksheet(2).Name);
             Assert.AreEqual(2, wb.Worksheets.Count);
         }
-        
+
+        [TestMethod]
+        public void RowCountTime()
+        {
+            var wb = new XLWorkbook();
+            var ws = wb.Worksheets.Add("Sheet1");
+            var start = DateTime.Now;
+            ws.RowCount();
+            var end = DateTime.Now;
+            Assert.IsTrue((end - start).TotalMilliseconds < 500);
+        }
+
+        [TestMethod]
+        public void ColumnCountTime()
+        {
+            var wb = new XLWorkbook();
+            var ws = wb.Worksheets.Add("Sheet1");
+            var start = DateTime.Now;
+            ws.ColumnCount();
+            var end = DateTime.Now;
+            Assert.IsTrue((end - start).TotalMilliseconds < 500);
+        }
     }
 }