diff --git a/CSharp/Libraries/UniversalEditor.Core/Accessor.cs b/CSharp/Libraries/UniversalEditor.Core/Accessor.cs
index 3d73d7c6..81c2c66c 100644
--- a/CSharp/Libraries/UniversalEditor.Core/Accessor.cs
+++ b/CSharp/Libraries/UniversalEditor.Core/Accessor.cs
@@ -19,7 +19,7 @@
 //  You should have received a copy of the GNU Lesser General Public License
 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -36,6 +36,19 @@ namespace UniversalEditor
 	[DebuggerNonUserCode()]
 	public abstract class Accessor : References<AccessorReference>
 	{
+		protected bool Initialized { get; private set; } = false;
+		protected void Initialize()
+		{
+			if (Initialized)
+				return;
+
+			InitializeInternal();
+			Initialized = true;
+		}
+		protected virtual void InitializeInternal()
+		{
+		}
+
 		/// <summary>
 		/// Creates or returns an existing <see cref="ReferencedBy" /> object referring to this <see cref="References" /> object.
 		/// </summary>
@@ -200,6 +213,13 @@ namespace UniversalEditor
 		{
 			get { return String.Empty; }
 		}
+
+		/// <summary>
+		/// Gets or sets the original URI.
+		/// </summary>
+		/// <value>The original URI.</value>
+		public Uri OriginalUri { get; set; }
+
 		/// <summary>
 		/// Gets the file name without path information for this <see cref="Accessor" />, if applicable.
 		/// </summary>
diff --git a/CSharp/Libraries/UniversalEditor.Core/AccessorReference.cs b/CSharp/Libraries/UniversalEditor.Core/AccessorReference.cs
index 89e6d665..47a66b67 100644
--- a/CSharp/Libraries/UniversalEditor.Core/AccessorReference.cs
+++ b/CSharp/Libraries/UniversalEditor.Core/AccessorReference.cs
@@ -21,6 +21,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Linq;
 using System.Text;
 
@@ -51,6 +52,8 @@ namespace UniversalEditor
 
 		private string mvarTitle = String.Empty;
 		public string Title { get { return mvarTitle; } set { mvarTitle = value; } }
+
+		public StringCollection Schemas { get; } = new StringCollection();
         
         /// <summary>
         /// Gets the detail fields that are shown in lists of this <see cref="ReferencedBy" /> object in details view.
diff --git a/CSharp/Libraries/UniversalEditor.Essential/Common/Reflection.cs b/CSharp/Libraries/UniversalEditor.Essential/Common/Reflection.cs
index c83d95fe..232f8cfe 100644
--- a/CSharp/Libraries/UniversalEditor.Essential/Common/Reflection.cs
+++ b/CSharp/Libraries/UniversalEditor.Essential/Common/Reflection.cs
@@ -494,6 +494,23 @@ namespace UniversalEditor.Common
 			if (mvarAvailableAccessors == null) Initialize();
 			return mvarAvailableAccessors;
 		}
+		public static AccessorReference[] GetAvailableAccessors(string fileName)
+		{
+			AccessorReference[] accrefs = GetAvailableAccessors();
+			List<AccessorReference> _list = new List<AccessorReference>();
+			foreach (AccessorReference ar in accrefs)
+			{
+				foreach (string schema in ar.Schemas)
+				{
+					if (fileName.StartsWith(schema + "://"))
+					{
+						_list.Add(ar);
+						break;
+					}
+				}
+			}
+			return _list.ToArray();
+		}
 		#endregion
 		#region Data Formats
 		private static DataFormatReference[] mvarAvailableDataFormats = null;
diff --git a/CSharp/Libraries/UniversalEditor.UserInterface/Engine.cs b/CSharp/Libraries/UniversalEditor.UserInterface/Engine.cs
index e784e284..56544035 100644
--- a/CSharp/Libraries/UniversalEditor.UserInterface/Engine.cs
+++ b/CSharp/Libraries/UniversalEditor.UserInterface/Engine.cs
@@ -591,12 +591,23 @@ namespace UniversalEditor.UserInterface
 		/// <param name="fileNames">The file name(s) of the document(s) to load.</param>
 		public void OpenWindow(params string[] fileNames)
 		{
-			Document[] documents = new Document[fileNames.Length];
+			List<Document> loadedDocuments = new List<Document>();
 			for (int i = 0; i < fileNames.Length; i++)
 			{
-				documents[i] = new Document(null, null, new FileAccessor(fileNames[i]));
+				AccessorReference[] accs = UniversalEditor.Common.Reflection.GetAvailableAccessors(fileNames[i]);
+				if (accs.Length > 0)
+				{
+					Accessor fa = accs[0].Create();
+					fa.OriginalUri = new Uri(fileNames[i]);
+					Document document = new Document(fa);
+					loadedDocuments.Add(document);
+				}
+				else
+				{
+					Console.Error.WriteLine("ue: accessor not found for path " + fileNames[i]);
+				}
 			}
-			OpenWindow(documents);
+			OpenWindow(loadedDocuments.ToArray());
 		}
 		/// <summary>
 		/// Opens a new window, optionally loading the specified documents.
diff --git a/CSharp/Libraries/UniversalEditor.UserInterface/MainWindow.cs b/CSharp/Libraries/UniversalEditor.UserInterface/MainWindow.cs
index b462fb9f..ebaf8d2c 100644
--- a/CSharp/Libraries/UniversalEditor.UserInterface/MainWindow.cs
+++ b/CSharp/Libraries/UniversalEditor.UserInterface/MainWindow.cs
@@ -543,8 +543,12 @@ namespace UniversalEditor.UserInterface
 			Document[] documents = new Document[fileNames.Length];
 			for (int i = 0; i < documents.Length; i++)
 			{
-				FileAccessor fa = new FileAccessor(fileNames[i]);
-				documents[i] = new Document(fa);
+				AccessorReference[] accs = UniversalEditor.Common.Reflection.GetAvailableAccessors(fileNames[i]);
+				if (accs.Length > 0)
+				{
+					Accessor fa = accs[0].Create();
+					documents[i] = new Document(fa);
+				}
 			}
 			OpenFile(documents);
 		}