diff --git a/NTwain/Data/Types.cs b/NTwain/Data/Types.cs
index 4c53871..dcff70f 100644
--- a/NTwain/Data/Types.cs
+++ b/NTwain/Data/Types.cs
@@ -101,7 +101,6 @@ namespace NTwain.Data
     BestFitMapping(false, ThrowOnUnmappableChar = true)]
     partial class TWAudioInfo
     {
-        // TODO: this may be wrong
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = TwainConst.String255)]
         string _name;
         TW_UINT32 _reserved;
@@ -173,7 +172,6 @@ namespace NTwain.Data
     partial class TWDeviceEvent
     {
         TW_UINT32 _event;
-        // TODO: may be wrong
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = TwainConst.String255)]
         string _deviceName;
         TW_UINT32 _batteryMinutes;
@@ -250,7 +248,7 @@ namespace NTwain.Data
         [FieldOffset(512)]
         TW_MEMREF _context;
 
-        //TODO: verify this field offset in 64bit
+        //TODO: verify this field offset in 64bit due to previous pointer
         [FieldOffset(520)]
         short _recursive;
         [FieldOffset(520)]
@@ -287,8 +285,6 @@ namespace NTwain.Data
         [FieldOffset(616)]
         TW_UINT32 _deviceGroupMask;
 
-        //TODO: verify this field, check if can just not use it
-        //char       _reserved[508]; /**/
         [FieldOffset(620)]
         [MarshalAs(UnmanagedType.ByValArray, SizeConst = 508)]
         TW_INT8[] _reserved;
diff --git a/NTwain/Data/TypesExtended.cs b/NTwain/Data/TypesExtended.cs
index d1f7879..0e31c42 100644
--- a/NTwain/Data/TypesExtended.cs
+++ b/NTwain/Data/TypesExtended.cs
@@ -1543,8 +1543,7 @@ namespace NTwain.Data
         /// information, such as the current directory.
         /// </summary>
         public IntPtr Context { get { return _context; } set { _context = value; } }
-        /* DG_CONTROL / DAT_FILESYSTEM / MSG_DELETE field    */
-        //TODO: verify this field
+        
         /// <summary>
         /// When set to TRUE recursively apply the operation. (ex: deletes
         /// all subdirectories in the directory being deleted; or copies all
diff --git a/NTwain/NTwain.csproj b/NTwain/NTwain.csproj
index 93cb51d..6610acb 100644
--- a/NTwain/NTwain.csproj
+++ b/NTwain/NTwain.csproj
@@ -70,6 +70,7 @@
     <Compile Include="Properties\VersionInfo.cs" />
     <Compile Include="TransferReadyEventArgs.cs" />
     <Compile Include="Triplets\DGControl\DGControl.Callback2.cs" />
+    <Compile Include="Triplets\DGImage\DGImage.Filter.cs" />
     <Compile Include="Triplets\OpBase.cs" />
     <Compile Include="Triplets\PInvokes.32bit.cs" />
     <Compile Include="Triplets\PInvokes.64bit.cs" />
diff --git a/NTwain/Triplets/DGControl/DGControl.Capability.cs b/NTwain/Triplets/DGControl/DGControl.Capability.cs
index 15b0f9a..e171825 100644
--- a/NTwain/Triplets/DGControl/DGControl.Capability.cs
+++ b/NTwain/Triplets/DGControl/DGControl.Capability.cs
@@ -124,5 +124,7 @@ namespace NTwain.Triplets
 			Session.VerifyState(4, 6, DataGroups.Control, DataArgumentType.Capability, Message.Set);
 			return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.Set, capability);
 		}
+
+        //TODO implement SetConstraint
 	}
 }
\ No newline at end of file
diff --git a/NTwain/Triplets/DGControl/DGControl.XferGroup.cs b/NTwain/Triplets/DGControl/DGControl.XferGroup.cs
index f9c37b3..08ad3d3 100644
--- a/NTwain/Triplets/DGControl/DGControl.XferGroup.cs
+++ b/NTwain/Triplets/DGControl/DGControl.XferGroup.cs
@@ -4,6 +4,8 @@ using NTwain.Values;
 
 namespace NTwain.Triplets
 {
+    // TODO: implement this
+
 	public sealed class XferGroup : OpBase
 	{
 		internal XferGroup(ITwainSessionInternal session) : base(session) { }
diff --git a/NTwain/Triplets/DGImage/DGImage.Filter.cs b/NTwain/Triplets/DGImage/DGImage.Filter.cs
new file mode 100644
index 0000000..67bb33c
--- /dev/null
+++ b/NTwain/Triplets/DGImage/DGImage.Filter.cs
@@ -0,0 +1,13 @@
+using NTwain.Data;
+using NTwain.Values;
+using System;
+
+namespace NTwain.Triplets
+{
+	public sealed class Filter : OpBase
+	{
+        internal Filter(ITwainSessionInternal session) : base(session) { }
+
+        //TODO: implement this
+	}
+}
\ No newline at end of file