diff --git a/BizHawk.Client.EmuHawk/CustomControls/HexTextBox.cs b/BizHawk.Client.EmuHawk/CustomControls/HexTextBox.cs
index 9887e4c240..47473edf5c 100644
--- a/BizHawk.Client.EmuHawk/CustomControls/HexTextBox.cs
+++ b/BizHawk.Client.EmuHawk/CustomControls/HexTextBox.cs
@@ -8,8 +8,8 @@ namespace BizHawk.Client.EmuHawk
 {
 	public interface INumberBox
 	{
-		int ToRawInt();
-		void SetFromRawInt(int rawint);
+		int? ToRawInt();
+		void SetFromRawInt(int? rawint);
 		bool Nullable { get; }
 	}
 
@@ -124,11 +124,18 @@ namespace BizHawk.Client.EmuHawk
 			base.OnTextChanged(e);
 		}
 
-		public int ToRawInt()
+		public int? ToRawInt()
 		{
 			if (String.IsNullOrWhiteSpace(Text))
 			{
-				return 0;
+				if (Nullable)
+				{
+					return null;
+				}
+				else
+				{
+					return 0;
+				}
 			}
 			else
 			{
@@ -136,9 +143,16 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
-		public void SetFromRawInt(int val)
+		public void SetFromRawInt(int? val)
 		{
-			Text = String.Format(_addressFormatStr, val);
+			if (val.HasValue)
+			{
+				Text = String.Empty;
+			}
+			else
+			{
+				Text = String.Format(_addressFormatStr, val);
+			}
 		}
 	}
 
@@ -227,11 +241,18 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
-		public int ToRawInt()
+		public int? ToRawInt()
 		{
 			if (String.IsNullOrWhiteSpace(Text))
 			{
-				return 0;
+				if (Nullable)
+				{
+					return null;
+				}
+				else
+				{
+					return 0;
+				}
 			}
 			else
 			{
@@ -239,9 +260,9 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
-		public void SetFromRawInt(int val)
+		public void SetFromRawInt(int? val)
 		{
-			Text = val.ToString();
+			Text = val.HasValue ? val.ToString() : String.Empty;
 		}
 	}
 }
diff --git a/BizHawk.Client.EmuHawk/tools/Cheats/CheatEdit.cs b/BizHawk.Client.EmuHawk/tools/Cheats/CheatEdit.cs
index 68b1bac140..c548dcdf87 100644
--- a/BizHawk.Client.EmuHawk/tools/Cheats/CheatEdit.cs
+++ b/BizHawk.Client.EmuHawk/tools/Cheats/CheatEdit.cs
@@ -273,7 +273,7 @@ namespace BizHawk.Client.EmuHawk
 			{
 				Watch watch = Watch.GenerateWatch(
 					Global.Emulator.MemoryDomains[DomainDropDown.SelectedItem.ToString()],
-					AddressBox.ToRawInt(),
+					AddressBox.ToRawInt().Value,
 					GetCurrentSize(),
 					Watch.StringToDisplayType(DisplayTypeDropDown.SelectedItem.ToString()),
 					NameBox.Text,
@@ -281,8 +281,8 @@ namespace BizHawk.Client.EmuHawk
 
 				return new Cheat(
 					watch,
-					ValueBox.ToRawInt(),
-					!String.IsNullOrWhiteSpace(CompareBox.Text) ? CompareBox.ToRawInt() : (int?)null
+					ValueBox.ToRawInt().Value,
+					 CompareBox.ToRawInt()
 				);
 			}
 		}
diff --git a/BizHawk.Client.EmuHawk/tools/Genesis/GenGameGenie.cs b/BizHawk.Client.EmuHawk/tools/Genesis/GenGameGenie.cs
index 733447fa51..552e37e565 100644
--- a/BizHawk.Client.EmuHawk/tools/Genesis/GenGameGenie.cs
+++ b/BizHawk.Client.EmuHawk/tools/Genesis/GenGameGenie.cs
@@ -269,7 +269,7 @@ namespace BizHawk.Client.EmuHawk
 
 				if (!String.IsNullOrWhiteSpace(ValueBox.Text))
 				{
-					VALUE = ValueBox.ToRawInt();
+					VALUE = ValueBox.ToRawInt().Value;
 				}
 
 				for (int i = 0; i < Global.Emulator.MemoryDomains.Count; i++)
diff --git a/BizHawk.Client.EmuHawk/tools/NES/NESGameGenie.cs b/BizHawk.Client.EmuHawk/tools/NES/NESGameGenie.cs
index 22219c4e0f..bc1693ad1c 100644
--- a/BizHawk.Client.EmuHawk/tools/NES/NESGameGenie.cs
+++ b/BizHawk.Client.EmuHawk/tools/NES/NESGameGenie.cs
@@ -151,22 +151,16 @@ namespace BizHawk.Client.EmuHawk
 			{
 				Watch watch = Watch.GenerateWatch(
 					Global.Emulator.MemoryDomains[1], /*System Bus*/
-					AddressBox.ToRawInt(),
+					AddressBox.ToRawInt().Value,
 					Watch.WatchSize.Byte,
 					Watch.DisplayType.Hex,
 					GameGenieCode.Text,
 					false);
 
-				int? compare = null;
-				if (!String.IsNullOrWhiteSpace(CompareBox.Text))
-				{
-					compare = CompareBox.ToRawInt();
-				}
-
 				Global.CheatList.Add(new Cheat(
 					watch,
-					ValueBox.ToRawInt(),
-					compare
+					ValueBox.ToRawInt().Value,
+					CompareBox.ToRawInt()
 				));
 			}
 		}
diff --git a/BizHawk.Client.EmuHawk/tools/Watch/WatchEditor.cs b/BizHawk.Client.EmuHawk/tools/Watch/WatchEditor.cs
index 1ba19b970d..7bebf799a7 100644
--- a/BizHawk.Client.EmuHawk/tools/Watch/WatchEditor.cs
+++ b/BizHawk.Client.EmuHawk/tools/Watch/WatchEditor.cs
@@ -200,7 +200,7 @@ namespace BizHawk.Client.EmuHawk
 				default:
 				case Mode.New:
 					var domain = Global.Emulator.MemoryDomains.FirstOrDefault(d => d.Name == DomainDropDown.SelectedItem.ToString());
-					var address = AddressBox.ToRawInt();
+					var address = AddressBox.ToRawInt().Value;
 					var notes = NotesBox.Text;
 					var type = Watch.StringToDisplayType(DisplayTypeDropDown.SelectedItem.ToString());
 					var bigendian = BigEndianCheckBox.Checked;
@@ -268,7 +268,7 @@ namespace BizHawk.Client.EmuHawk
 					string tempNotes = _watchList[i].Notes;
 					_watchList[i] = Watch.GenerateWatch(
 						_watchList[i].Domain,
-						_watchList.Count == 1 ? AddressBox.ToRawInt() : _watchList[i].Address.Value,
+						_watchList.Count == 1 ? AddressBox.ToRawInt().Value : _watchList[i].Address.Value,
 						size,
 						_watchList[i].Type,
 						_watchList[i].Notes,
diff --git a/BizHawk.Client.EmuHawk/tools/Watch/WatchValueBox.cs b/BizHawk.Client.EmuHawk/tools/Watch/WatchValueBox.cs
index 450c3efa66..e48238bcaf 100644
--- a/BizHawk.Client.EmuHawk/tools/Watch/WatchValueBox.cs
+++ b/BizHawk.Client.EmuHawk/tools/Watch/WatchValueBox.cs
@@ -75,7 +75,7 @@ namespace BizHawk.Client.EmuHawk
 			get { return _type; }
 			set
 			{
-				int val = ToRawInt();
+				int? val = ToRawInt();
 				_type = value;
 				SetMaxLength();
 				SetFromRawInt(val);
@@ -227,14 +227,19 @@ namespace BizHawk.Client.EmuHawk
 
 		protected override void OnKeyDown(KeyEventArgs e)
 		{
+			string text = String.IsNullOrWhiteSpace(Text) ? "0" : Text;
 			if (e.KeyCode == Keys.Up)
 			{
 				switch (_type)
 				{
 					default:
 					case Watch.DisplayType.Signed:
-						int val = ToRawInt();
-						if (val == MaxSignedInt)
+						int? val = ToRawInt() ?? 0;
+						if (!val.HasValue)
+						{
+							Text = String.Empty;
+						}
+						else if (val == MaxSignedInt)
 						{
 							val = 0;
 						}
@@ -245,7 +250,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = val.ToString();
 						break;
 					case Watch.DisplayType.Unsigned:
-						uint uval = (uint)ToRawInt();
+						uint uval = (uint)(ToRawInt() ?? 0);
 						if (uval == MaxUnsignedInt)
 						{
 							uval = 0;
@@ -257,7 +262,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = uval.ToString();
 						break;
 					case Watch.DisplayType.Binary:
-						uint bval = (uint)ToRawInt();
+						uint bval = (uint)(ToRawInt() ?? 0);
 						if (bval == MaxUnsignedInt)
 						{
 							bval = 0;
@@ -270,7 +275,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = Convert.ToString(bval, 2).PadLeft(numBits, '0');
 						break;
 					case Watch.DisplayType.Hex:
-						uint hexVal = (uint)ToRawInt();
+						uint hexVal = (uint)(ToRawInt() ?? 0);
 						if (hexVal == MaxUnsignedInt)
 						{
 							hexVal = 0;
@@ -282,7 +287,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = hexVal.ToHexString(MaxLength);
 						break;
 					case Watch.DisplayType.FixedPoint_12_4:
-						double f12val = double.Parse(Text);
+						double f12val = double.Parse(text);
 						if (f12val > Max12_4 - _12_4_Unit)
 						{
 							f12val = 0;
@@ -294,7 +299,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = f12val.ToString();
 						break;
 					case Watch.DisplayType.FixedPoint_20_12:
-						double f24val = double.Parse(Text);
+						double f24val = double.Parse(text);
 						if (f24val >= Max20_12 - _20_12_Unit)
 						{
 							f24val = 0;
@@ -306,7 +311,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = f24val.ToString();
 						break;
 					case Watch.DisplayType.Float:
-						double dval = double.Parse(Text);
+						double dval = double.Parse(text);
 						if (dval > double.MaxValue - 1)
 						{
 							dval = 0;
@@ -325,8 +330,12 @@ namespace BizHawk.Client.EmuHawk
 				{
 					default:
 					case Watch.DisplayType.Signed:
-						int val = ToRawInt();
-						if (val == 0)
+						int? val = ToRawInt();
+						if (!val.HasValue)
+						{
+							Text = String.Empty;
+						}
+						else if (val == 0)
 						{
 							val = MaxSignedInt;
 						}
@@ -362,7 +371,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = Convert.ToString(bval, 2).PadLeft(numBits, '0');
 						break;
 					case Watch.DisplayType.Hex:
-						uint hexVal = (uint)ToRawInt();
+						uint hexVal = (uint)(ToRawInt() ?? 0);
 						if (hexVal == 0)
 						{
 							hexVal = MaxUnsignedInt;
@@ -374,7 +383,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = hexVal.ToHexString(MaxLength);
 						break;
 					case Watch.DisplayType.FixedPoint_12_4:
-						double f12val = double.Parse(Text);
+						double f12val = double.Parse(text);
 						if (f12val < 0 + _12_4_Unit)
 						{
 							f12val = Max12_4;
@@ -386,7 +395,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = f12val.ToString();
 						break;
 					case Watch.DisplayType.FixedPoint_20_12:
-						double f24val = double.Parse(Text);
+						double f24val = double.Parse(text);
 						if (f24val < 0 + _20_12_Unit)
 						{
 							f24val = Max20_12;
@@ -398,7 +407,7 @@ namespace BizHawk.Client.EmuHawk
 						Text = f24val.ToString();
 						break;
 					case Watch.DisplayType.Float:
-						double dval = double.Parse(Text);
+						double dval = double.Parse(text);
 						if (dval > double.MaxValue - 1)
 						{
 							dval = 0;
@@ -478,11 +487,18 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
-		public int ToRawInt()
+		public int? ToRawInt()
 		{
 			if (String.IsNullOrWhiteSpace(Text))
 			{
-				return 0;
+				if (Nullable)
+				{
+					return null;
+				}
+				else
+				{
+					return 0;
+				}
 			}
 			else
 			{
@@ -509,37 +525,44 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
-		public void SetFromRawInt(int val)
+		public void SetFromRawInt(int? val)
 		{
-			switch (_type)
+			if (val.HasValue)
 			{
-				default:
-				case Watch.DisplayType.Signed:
-					Text = val.ToString();
-					break;
-				case Watch.DisplayType.Unsigned:
-					uint uval = (uint)val;
-					Text = uval.ToString();
-					break;
-				case Watch.DisplayType.Binary:
-					uint bval = (uint)val;
-					int numBits = ((int)ByteSize) * 8;
-					Text = Convert.ToString(bval, 2).PadLeft(numBits, '0');
-					break;
-				case Watch.DisplayType.Hex:
-					Text = val.ToHexString(MaxLength);
-					break;
-				case Watch.DisplayType.FixedPoint_12_4:
-					Text = String.Format("{0:F5}", (val / 16.0));
-					break;
-				case Watch.DisplayType.FixedPoint_20_12:
-					Text = String.Format("{0:F5}", (val / 4096.0));
-					break;
-				case Watch.DisplayType.Float:
-					byte[] bytes = BitConverter.GetBytes(val);
-					float _float = BitConverter.ToSingle(bytes, 0);
-					Text = String.Format("{0:F6}", _float);
-					break;
+				switch (_type)
+				{
+					default:
+					case Watch.DisplayType.Signed:
+						Text = val.ToString();
+						break;
+					case Watch.DisplayType.Unsigned:
+						uint uval = (uint)val.Value;
+						Text = uval.ToString();
+						break;
+					case Watch.DisplayType.Binary:
+						uint bval = (uint)val.Value;
+						int numBits = ((int)ByteSize) * 8;
+						Text = Convert.ToString(bval, 2).PadLeft(numBits, '0');
+						break;
+					case Watch.DisplayType.Hex:
+						Text = val.Value.ToHexString(MaxLength);
+						break;
+					case Watch.DisplayType.FixedPoint_12_4:
+						Text = String.Format("{0:F5}", (val.Value / 16.0));
+						break;
+					case Watch.DisplayType.FixedPoint_20_12:
+						Text = String.Format("{0:F5}", (val.Value / 4096.0));
+						break;
+					case Watch.DisplayType.Float:
+						byte[] bytes = BitConverter.GetBytes(val.Value);
+						float _float = BitConverter.ToSingle(bytes, 0);
+						Text = String.Format("{0:F6}", _float);
+						break;
+				}
+			}
+			else
+			{
+				Text = String.Empty;
 			}
 		}
 	}