diff --git a/src/Avalonia.Controls/ISelectionModel.cs b/src/Avalonia.Controls/ISelectionModel.cs
index 34fe626696..6570921c03 100644
--- a/src/Avalonia.Controls/ISelectionModel.cs
+++ b/src/Avalonia.Controls/ISelectionModel.cs
@@ -9,45 +9,241 @@ using System.ComponentModel;
 
 namespace Avalonia.Controls
 {
+    /// <summary>
+    /// Holds the selected items for a control.
+    /// </summary>
     public interface ISelectionModel : INotifyPropertyChanged
     {
+        /// <summary>
+        /// Gets or sets the anchor index.
+        /// </summary>
         IndexPath AnchorIndex { get; set; }
+
+        /// <summary>
+        /// Gets or set the index of the first selected item.
+        /// </summary>
         IndexPath SelectedIndex { get; set; }
+
+        /// <summary>
+        /// Gets or set the indexes of the selected items.
+        /// </summary>
         IReadOnlyList<IndexPath> SelectedIndices { get; }
+
+        /// <summary>
+        /// Gets the first selected item.
+        /// </summary>
         object SelectedItem { get; }
+
+        /// <summary>
+        /// Gets the selected items.
+        /// </summary>
         IReadOnlyList<object> SelectedItems { get; }
+        
+        /// <summary>
+        /// Gets a value indicating whether the model represents a single or multiple selection.
+        /// </summary>
         bool SingleSelect { get; set; }
+
+        /// <summary>
+        /// Gets a value indicating whether to always keep an item selected where possible.
+        /// </summary>
         bool AutoSelect { get; set; }
+
+        /// <summary>
+        /// Gets or sets the collection that contains the items that can be selected.
+        /// </summary>
         object Source { get; set; }
 
+        /// <summary>
+        /// Raised when the children of a selection are required.
+        /// </summary>
         event EventHandler<SelectionModelChildrenRequestedEventArgs> ChildrenRequested;
+
+        /// <summary>
+        /// Raised when the selection has changed.
+        /// </summary>
         event EventHandler<SelectionModelSelectionChangedEventArgs> SelectionChanged;
 
+        /// <summary>
+        /// Clears the selection.
+        /// </summary>
         void ClearSelection();
+
+        /// <summary>
+        /// Deselects an item.
+        /// </summary>
+        /// <param name="index">The index of the item.</param>
         void Deselect(int index);
+
+        /// <summary>
+        /// Deselects an item.
+        /// </summary>
+        /// <param name="groupIndex">The index of the item group.</param>
+        /// <param name="itemIndex">The index of the item in the group.</param>
         void Deselect(int groupIndex, int itemIndex);
+
+        /// <summary>
+        /// Deselects an item.
+        /// </summary>
+        /// <param name="index">The index of the item.</param>
         void DeselectAt(IndexPath index);
+
+        /// <summary>
+        /// Deselects a range of items.
+        /// </summary>
+        /// <param name="start">The start index of the range.</param>
+        /// <param name="end">The end index of the range.</param>
         void DeselectRange(IndexPath start, IndexPath end);
+
+        /// <summary>
+        /// Deselects a range of items, starting at <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="index">The end index of the range.</param>
         void DeselectRangeFromAnchor(int index);
+
+        /// <summary>
+        /// Deselects a range of items, starting at <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="endGroupIndex">
+        /// The index of the item group that represents the end of the selection.
+        /// </param>
+        /// <param name="endItemIndex">
+        /// The index of the item in the group that represents the end of the selection.
+        /// </param>
         void DeselectRangeFromAnchor(int endGroupIndex, int endItemIndex);
+
+        /// <summary>
+        /// Deselects a range of items, starting at <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="index">The end index of the range.</param>
         void DeselectRangeFromAnchorTo(IndexPath index);
+
+        /// <summary>
+        /// Disposes the object and clears the selection.
+        /// </summary>
         void Dispose();
+
+        /// <summary>
+        /// Checks whether an item is selected.
+        /// </summary>
+        /// <param name="index">The index of the item</param>
         bool IsSelected(int index);
-        bool IsSelected(int grouIndex, int itemIndex);
+
+        /// <summary>
+        /// Checks whether an item is selected.
+        /// </summary>
+        /// <param name="groupIndex">The index of the item group.</param>
+        /// <param name="itemIndex">The index of the item in the group.</param>
+        bool IsSelected(int groupIndex, int itemIndex);
+
+        /// <summary>
+        /// Checks whether an item is selected.
+        /// </summary>
+        /// <param name="index">The index of the item</param>
         public bool IsSelectedAt(IndexPath index);
+
+        /// <summary>
+        /// Checks whether an item or its descendents are selected.
+        /// </summary>
+        /// <param name="index">The index of the item</param>
+        /// <returns>
+        /// True if the item and all its descendents are selected, false if the item and all its
+        /// descendents are deselected, or null if a combination of selected and deselected.
+        /// </returns>
         bool? IsSelectedWithPartial(int index);
+
+        /// <summary>
+        /// Checks whether an item or its descendents are selected.
+        /// </summary>
+        /// <param name="groupIndex">The index of the item group.</param>
+        /// <param name="itemIndex">The index of the item in the group.</param>
+        /// <returns>
+        /// True if the item and all its descendents are selected, false if the item and all its
+        /// descendents are deselected, or null if a combination of selected and deselected.
+        /// </returns>
         bool? IsSelectedWithPartial(int groupIndex, int itemIndex);
+
+        /// <summary>
+        /// Checks whether an item or its descendents are selected.
+        /// </summary>
+        /// <param name="index">The index of the item</param>
+        /// <returns>
+        /// True if the item and all its descendents are selected, false if the item and all its
+        /// descendents are deselected, or null if a combination of selected and deselected.
+        /// </returns>
         bool? IsSelectedWithPartialAt(IndexPath index);
+
+        /// <summary>
+        /// Selects an item.
+        /// </summary>
+        /// <param name="index">The index of the item</param>
         void Select(int index);
+
+        /// <summary>
+        /// Selects an item.
+        /// </summary>
+        /// <param name="groupIndex">The index of the item group.</param>
+        /// <param name="itemIndex">The index of the item in the group.</param>
         void Select(int groupIndex, int itemIndex);
-        void SelectAll();
+
+        /// <summary>
+        /// Selects an item.
+        /// </summary>
+        /// <param name="index">The index of the item</param>
         void SelectAt(IndexPath index);
+
+        /// <summary>
+        /// Selects all items.
+        /// </summary>
+        void SelectAll();
+
+        /// <summary>
+        /// Selects a range of items.
+        /// </summary>
+        /// <param name="start">The start index of the range.</param>
+        /// <param name="end">The end index of the range.</param>
         void SelectRange(IndexPath start, IndexPath end);
+
+        /// <summary>
+        /// Selects a range of items, starting at <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="index">The end index of the range.</param>
         void SelectRangeFromAnchor(int index);
+
+        /// <summary>
+        /// Selects a range of items, starting at <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="endGroupIndex">
+        /// The index of the item group that represents the end of the selection.
+        /// </param>
+        /// <param name="endItemIndex">
+        /// The index of the item in the group that represents the end of the selection.
+        /// </param>
         void SelectRangeFromAnchor(int endGroupIndex, int endItemIndex);
+
+        /// <summary>
+        /// Selects a range of items, starting at <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="index">The end index of the range.</param>
         void SelectRangeFromAnchorTo(IndexPath index);
+
+        /// <summary>
+        /// Sets the <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="index">The anchor index.</param>
         void SetAnchorIndex(int index);
+
+        /// <summary>
+        /// Sets the <see cref="AnchorIndex"/>.
+        /// </summary>
+        /// <param name="groupIndex">The index of the item group.</param>
+        /// <param name="index">The index of the item in the group.</param>
         void SetAnchorIndex(int groupIndex, int index);
+
+        /// <summary>
+        /// Begins a batch update of the selection.
+        /// </summary>
+        /// <returns>An <see cref="IDisposable"/> that finishes the batch update.</returns>
         IDisposable Update();
     }
 }