diff --git a/src/Avalonia.Controls.DataGrid/DataGridRows.cs b/src/Avalonia.Controls.DataGrid/DataGridRows.cs
index a69b8eafe1..4bfbd7d818 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRows.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRows.cs
@@ -425,7 +425,7 @@ namespace Avalonia.Controls
                 UpdateDisplayedRows(DisplayData.FirstScrollingSlot, CellsHeight);
             }
 
-            if (DisplayData.FirstScrollingSlot < slot && DisplayData.LastScrollingSlot > slot)
+            if (DisplayData.FirstScrollingSlot < slot && (DisplayData.LastScrollingSlot > slot || DisplayData.LastScrollingSlot == -1))
             {
                 // The row is already displayed in its entirety
                 return true;
diff --git a/src/Avalonia.Controls/ComboBox.cs b/src/Avalonia.Controls/ComboBox.cs
index f8728af87f..dd2109e6cd 100644
--- a/src/Avalonia.Controls/ComboBox.cs
+++ b/src/Avalonia.Controls/ComboBox.cs
@@ -205,7 +205,7 @@ namespace Avalonia.Controls
             if (e.Handled)
                 return;
 
-            if (e.Key == Key.F4 ||
+            if ((e.Key == Key.F4 && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt) == false) ||
                 ((e.Key == Key.Down || e.Key == Key.Up) && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt)))
             {
                 IsDropDownOpen = !IsDropDownOpen;
diff --git a/src/Avalonia.Controls/GridLength.cs b/src/Avalonia.Controls/GridLength.cs
index b8418949d9..ee6a146d61 100644
--- a/src/Avalonia.Controls/GridLength.cs
+++ b/src/Avalonia.Controls/GridLength.cs
@@ -77,6 +77,12 @@ namespace Avalonia.Controls
         /// </summary>
         public static GridLength Auto => new GridLength(0, GridUnitType.Auto);
 
+        /// <summary>
+        /// Gets an instance of <see cref="GridLength"/> that indicates that a row or column should
+        /// fill its content.
+        /// </summary>
+        public static GridLength Star => new GridLength(1, GridUnitType.Star);
+
         /// <summary>
         /// Gets the unit of the <see cref="GridLength"/>.
         /// </summary>
diff --git a/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs b/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs
index b0b52812b9..e3783febdd 100644
--- a/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs
+++ b/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs
@@ -511,8 +511,8 @@ namespace Avalonia.Controls.Presenters
             else if (scrollable.IsLogicalScrollEnabled)
             {
                 Viewport = scrollable.Viewport;
-                Extent = scrollable.Extent;
                 Offset = scrollable.Offset;
+                Extent = scrollable.Extent;
             }
         }
 
diff --git a/src/Avalonia.Controls/RowDefinitions.cs b/src/Avalonia.Controls/RowDefinitions.cs
index 02ab12b5af..a5ed6ae09d 100644
--- a/src/Avalonia.Controls/RowDefinitions.cs
+++ b/src/Avalonia.Controls/RowDefinitions.cs
@@ -1,5 +1,4 @@
 using System.Linq;
-using Avalonia.Collections;
 
 namespace Avalonia.Controls
 {
@@ -25,6 +24,11 @@ namespace Avalonia.Controls
             AddRange(GridLength.ParseLengths(s).Select(x => new RowDefinition(x)));
         }
 
+        public override string ToString()
+        {
+            return string.Join(",", this.Select(x => x.Height));
+        }
+
         /// <summary>
         /// Parses a string representation of row definitions collection.
         /// </summary>
@@ -32,4 +36,4 @@ namespace Avalonia.Controls
         /// <returns>The <see cref="RowDefinitions"/>.</returns>
         public static RowDefinitions Parse(string s) => new RowDefinitions(s);
     }
-}
\ No newline at end of file
+}
diff --git a/src/Avalonia.Visuals/Media/BoxShadow.cs b/src/Avalonia.Visuals/Media/BoxShadow.cs
index 69395fd3b8..50f75365b0 100644
--- a/src/Avalonia.Visuals/Media/BoxShadow.cs
+++ b/src/Avalonia.Visuals/Media/BoxShadow.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Globalization;
+using System.Text;
 using Avalonia.Animation.Animators;
 using Avalonia.Utilities;
 
@@ -75,6 +76,46 @@ namespace Avalonia.Media
                 return rv;
             }
         }
+
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+
+            if (IsEmpty)
+            {
+                return "none";
+            }
+
+            if (IsInset)
+            {
+                sb.Append("inset");
+            }
+
+            if (OffsetX != 0.0)
+            {
+                sb.AppendFormat(" {0}", OffsetX.ToString());
+            }
+
+            if (OffsetY != 0.0)
+            {
+                sb.AppendFormat(" {0}", OffsetY.ToString());
+            }
+            
+            if (Blur != 0.0)
+            {
+                sb.AppendFormat(" {0}", Blur.ToString());
+            }
+
+            if (Spread != 0.0)
+            {
+                sb.AppendFormat(" {0}", Spread.ToString());
+            }
+
+            sb.AppendFormat(" {0}", Color.ToString());
+
+            return sb.ToString();
+        }
+
         public static unsafe BoxShadow Parse(string s)
         {
             if(s == null)
diff --git a/src/Avalonia.Visuals/Media/BoxShadows.cs b/src/Avalonia.Visuals/Media/BoxShadows.cs
index 9e4d6aacb0..810ac70b99 100644
--- a/src/Avalonia.Visuals/Media/BoxShadows.cs
+++ b/src/Avalonia.Visuals/Media/BoxShadows.cs
@@ -1,6 +1,6 @@
 using System;
-using System.Collections.Generic;
 using System.ComponentModel;
+using System.Text;
 using Avalonia.Animation.Animators;
 
 namespace Avalonia.Media
@@ -43,6 +43,24 @@ namespace Avalonia.Media
             }
         }
 
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+
+            if (Count == 0)
+            {
+                return "none";
+            }
+
+            foreach (var boxShadow in this)
+            {
+                sb.AppendFormat("{0} ", boxShadow.ToString());
+            }
+
+            return sb.ToString();
+
+        }
+
         [EditorBrowsable(EditorBrowsableState.Never)]
         public struct BoxShadowsEnumerator
         {
diff --git a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
index 8f9c7fdb0b..cb2fd11175 100644
--- a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
@@ -201,6 +201,65 @@ namespace Avalonia.Controls.UnitTests
                 
             }
             
-        } 
+        }
+
+        [Fact]
+        public void Close_Window_On_Alt_F4_When_ComboBox_Is_Focus()
+        {
+            var inputManagerMock = new Moq.Mock<IInputManager>();
+            var services = TestServices.StyledWindow.With(inputManager: inputManagerMock.Object);
+
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var window = new Window();
+
+                window.KeyDown += (s, e) =>
+                 {
+                     if (e.Handled == false 
+                     && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt) == true 
+                     && e.Key == Key.F4 )
+                     {
+                         e.Handled = true;
+                         window.Close();
+                     }
+                 };
+
+                var count = 0;
+
+                var target = new ComboBox
+                {
+                    Items = new[] { new Canvas() },
+                    SelectedIndex = 0,
+                    Template = GetTemplate(),
+                };
+
+                window.Content = target;
+
+
+                window.Closing +=
+                    (sender, e) =>
+                    {
+                        count++;
+                    };
+
+                window.Show();
+
+                target.Focus();
+
+                _helper.Down(target);
+                _helper.Up(target);
+                Assert.True(target.IsDropDownOpen);
+
+                target.RaiseEvent(new KeyEventArgs
+                {
+                    RoutedEvent = InputElement.KeyDownEvent,
+                    KeyModifiers = KeyModifiers.Alt,
+                    Key = Key.F4
+                });
+
+
+                Assert.Equal(1, count);
+            }
+        }
     }
 }