diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index 830d17674a..ed92899cc6 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -148,7 +148,8 @@ namespace Avalonia.Controls
             {
                 value = CoerceCaretIndex(value);
                 SetAndRaise(CaretIndexProperty, ref _caretIndex, value);
-                if (_undoRedoHelper.IsLastState && _undoRedoHelper.LastState.Text == Text)
+                UndoRedoState state;
+                if (_undoRedoHelper.TryGetLastState(out state) && state.Text == Text)
                     _undoRedoHelper.UpdateLastState();
             }
         }
@@ -732,7 +733,7 @@ namespace Avalonia.Controls
         private void SelectAll()
         {
             SelectionStart = 0;
-            SelectionEnd = Text.Length;
+            SelectionEnd = Text?.Length ?? 0;
         }
 
         private bool DeleteSelection()
diff --git a/src/Avalonia.Controls/Utils/UndoRedoHelper.cs b/src/Avalonia.Controls/Utils/UndoRedoHelper.cs
index 2301198a01..71ba3793d1 100644
--- a/src/Avalonia.Controls/Utils/UndoRedoHelper.cs
+++ b/src/Avalonia.Controls/Utils/UndoRedoHelper.cs
@@ -8,20 +8,19 @@ using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Utils
 {
-    class UndoRedoHelper<TState> : WeakTimer.IWeakTimerSubscriber where TState : IEquatable<TState>
+    class UndoRedoHelper<TState> : WeakTimer.IWeakTimerSubscriber where TState : struct, IEquatable<TState>
     {
         private readonly IUndoRedoHost _host;
 
         public interface IUndoRedoHost
         {
-             TState UndoRedoState { get; set; }
+            TState UndoRedoState { get; set; }
         }
-        
+
 
 
         private readonly LinkedList<TState> _states = new LinkedList<TState>();
 
-        [NotNull]
         private LinkedListNode<TState> _currentNode;
 
         public int Limit { get; set; } = 10;
@@ -29,24 +28,31 @@ namespace Avalonia.Controls.Utils
         public UndoRedoHelper(IUndoRedoHost host)
         {
             _host = host;
-            _states.AddFirst(_host.UndoRedoState);
-            _currentNode = _states.First;
-            WeakTimer.StartWeakTimer(this, new TimeSpan(0, 0, 1));
-
+            WeakTimer.StartWeakTimer(this, TimeSpan.FromSeconds(1));
         }
 
         public void Undo()
         {
-			if (_currentNode?.Previous != null)  
-			{
-				_currentNode = _currentNode.Previous;
-			}
-
-			_host.UndoRedoState = _currentNode.Value;            
+            if (_currentNode?.Previous != null)
+            {
+                _currentNode = _currentNode.Previous;
+                _host.UndoRedoState = _currentNode.Value;
+            }
         }
 
-        public bool IsLastState => _currentNode.Next == null;
+        public bool IsLastState => _currentNode != null && _currentNode.Next == null;
+
+        public bool TryGetLastState(out TState _state)
+        {
+            _state = default(TState);
+            if (!IsLastState)
+                return false;
 
+            _state = _currentNode.Value;
+            return true;
+        }
+
+        public bool HasState => _currentNode != null;
         public void UpdateLastState(TState state)
         {
             _states.Last.Value = state;
@@ -57,34 +63,31 @@ namespace Avalonia.Controls.Utils
             _states.Last.Value = _host.UndoRedoState;
         }
 
-        public TState LastState => _currentNode.Value;
-
         public void DiscardRedo()
         {
-            //Linked list sucks, so we are doing this
-            while (_currentNode.Next != null)
+            while (_currentNode?.Next != null)
                 _states.Remove(_currentNode.Next);
         }
 
         public void Redo()
-        {            
-			if (_currentNode?.Next != null) {
-				_currentNode = _currentNode.Next;
-			}
-
-			_host.UndoRedoState = _currentNode.Value;
+        {
+            if (_currentNode?.Next != null)
+            {
+                _currentNode = _currentNode.Next;
+                _host.UndoRedoState = _currentNode.Value;
+            }
         }
 
         public void Snapshot()
         {
             var current = _host.UndoRedoState;
-            if (!_currentNode.Value.Equals(current))
+            if (_currentNode == null || !_currentNode.Value.Equals(current))
             {
-                if(_currentNode.Next != null)
+                if (_currentNode?.Next != null)
                     DiscardRedo();
                 _states.AddLast(current);
                 _currentNode = _states.Last;
-                if(_states.Count > Limit)
+                if (_states.Count > Limit)
                     _states.RemoveFirst();
             }
         }
diff --git a/src/Skia/Avalonia.Skia/FormattedTextImpl.cs b/src/Skia/Avalonia.Skia/FormattedTextImpl.cs
index 5a93538757..e24b6053b0 100644
--- a/src/Skia/Avalonia.Skia/FormattedTextImpl.cs
+++ b/src/Skia/Avalonia.Skia/FormattedTextImpl.cs
@@ -28,7 +28,9 @@ namespace Avalonia.Skia
             //Paint.TextEncoding = SKTextEncoding.Utf8;
             _paint.TextEncoding = SKTextEncoding.Utf16;
             _paint.IsStroke = false;
-            _paint.IsAntialias = true;
+            _paint.IsAntialias = true;            
+            _paint.LcdRenderText = true;            
+            _paint.SubpixelText = true;
             _paint.Typeface = typeface;
             _paint.TextSize = (float)fontSize;
             _paint.TextAlign = textAlignment.ToSKTextAlign();
diff --git a/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs b/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
index 168d9786c2..851657ab6c 100644
--- a/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
@@ -41,6 +41,58 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Press_Ctrl_A_Select_All_Text()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var target = new TextBox
+                {
+                    Template = CreateTemplate(),
+                    Text = "1234"
+                };
+
+                RaiseKeyEvent(target, Key.A, InputModifiers.Control);
+
+                Assert.Equal(0, target.SelectionStart);
+                Assert.Equal(4, target.SelectionEnd);
+            }
+        }
+
+        [Fact]
+        public void Press_Ctrl_A_Select_All_Null_Text()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var target = new TextBox
+                {
+                    Template = CreateTemplate()
+                };
+
+                RaiseKeyEvent(target, Key.A, InputModifiers.Control);
+
+                Assert.Equal(0, target.SelectionStart);
+                Assert.Equal(0, target.SelectionEnd);
+            }
+        }
+
+        [Fact]
+        public void Press_Ctrl_Z_Will_Not_Modify_Text()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var target = new TextBox
+                {
+                    Template = CreateTemplate(),
+                    Text = "1234"
+                };
+
+                RaiseKeyEvent(target, Key.Z, InputModifiers.Control);
+
+                Assert.Equal("1234", target.Text);
+            }
+        }
+
         [Fact]
         public void Typing_Beginning_With_0_Should_Not_Modify_Text_When_Bound_To_Int()
         {