fix an oops in last commit, and fix adding cheats via Cheats cheat form

BizHawk.Client.Common/tools/CheatList.cs

@@ -103,7 +103,11 @@ namespace BizHawk.Client.Common
 
 		public void Add(Cheat cheat)
 		{
-			if (!cheat.IsSeparator)
+			if (cheat.IsSeparator)
+			{
+				_cheatList.Add(cheat);
+			}
+			else
 			{
 				cheat.Changed += CheatChanged;
 				if (_cheatList.Any(x => x.Domain == cheat.Domain && x.Address == cheat.Address))
@@ -116,7 +120,6 @@ namespace BizHawk.Client.Common
 				}
 			}
 
-			_cheatList.Add(cheat);
 			Changes = true;
 		}
 

BizHawk.Client.EmuHawk/tools/Cheats/CheatEdit.cs

@@ -266,7 +266,7 @@ namespace BizHawk.Client.EmuHawk
 		{
 			get
 			{
-				Watch w = Watch.GenerateWatch(
+				Watch watch = Watch.GenerateWatch(
 					ToolHelpers.DomainByName(DomainDropDown.SelectedItem.ToString()),
 					AddressBox.ToRawInt(),
 					GetCurrentSize(),
@@ -274,7 +274,11 @@ namespace BizHawk.Client.EmuHawk
 					NameBox.Text,
 					BigEndianCheckBox.Checked);
 
-				return new Cheat(w, CompareBox.ToRawInt(), enabled: true);
+				return new Cheat(
+					watch,
+					ValueBox.ToRawInt(),
+					!String.IsNullOrWhiteSpace(CompareBox.Text) ? CompareBox.ToRawInt() : (int?)null
+				);
 			}
 		}