diff --git a/Source/General/MapManager.cs b/Source/General/MapManager.cs
index 4862b5aa..56b1597c 100644
--- a/Source/General/MapManager.cs
+++ b/Source/General/MapManager.cs
@@ -475,6 +475,15 @@ namespace CodeImp.DoomBuilder
 
 			try
 			{
+				// Backup existing file, if any
+				if(File.Exists(newfilepathname))
+				{
+					if(File.Exists(newfilepathname + ".backup3")) File.Delete(newfilepathname + ".backup3");
+					if(File.Exists(newfilepathname + ".backup2")) File.Move(newfilepathname + ".backup2", newfilepathname + ".backup3");
+					if(File.Exists(newfilepathname + ".backup1")) File.Move(newfilepathname + ".backup1", newfilepathname + ".backup2");
+					File.Copy(newfilepathname, newfilepathname + ".backup1");
+				}
+				
 				// Except when saving INTO another file,
 				// kill the target file if it is different from source file
 				if((savemode != SAVE_INTO) && (newfilepathname != filepathname))
diff --git a/Source/IO/DoomMapSetIO.cs b/Source/IO/DoomMapSetIO.cs
index b7fe9109..df6712d2 100644
--- a/Source/IO/DoomMapSetIO.cs
+++ b/Source/IO/DoomMapSetIO.cs
@@ -121,7 +121,7 @@ namespace CodeImp.DoomBuilder.IO
 				
 				// Create new item
 				t = map.CreateThing();
-				t.Update(type, x, y, 0, angle, stringflags, 0, 0, Thing.EMPTY_ARGS);
+				t.Update(type, x, y, 0, angle, stringflags, 0, 0, new int[Thing.NUM_ARGS]);
 				//t.DetermineSector();
 				t.UpdateConfiguration();
 			}
@@ -274,7 +274,7 @@ namespace CodeImp.DoomBuilder.IO
 
 				// Create new item
 				l = map.CreateLinedef(vertexlink[v1], vertexlink[v2]);
-				l.Update(stringflags, 0, tag, action, Linedef.EMPTY_ARGS);
+				l.Update(stringflags, 0, tag, action, new int[Linedef.NUM_ARGS]);
 				l.UpdateCache();
 
 				// Line has a front side?
diff --git a/Source/Map/Linedef.cs b/Source/Map/Linedef.cs
index 19fd673a..84a549cf 100644
--- a/Source/Map/Linedef.cs
+++ b/Source/Map/Linedef.cs
@@ -38,7 +38,6 @@ namespace CodeImp.DoomBuilder.Map
 
 		public const float SIDE_POINT_DISTANCE = 0.001f;
 		public const int NUM_ARGS = 5;
-		public static readonly int[] EMPTY_ARGS = new int[NUM_ARGS];
 		
 		#endregion
 
diff --git a/Source/Map/Thing.cs b/Source/Map/Thing.cs
index 8532360a..1e95f559 100644
--- a/Source/Map/Thing.cs
+++ b/Source/Map/Thing.cs
@@ -37,7 +37,6 @@ namespace CodeImp.DoomBuilder.Map
 		#region ================== Constants
 
 		public const int NUM_ARGS = 5;
-		public static readonly int[] EMPTY_ARGS = new int[NUM_ARGS];
 
 		#endregion
 
@@ -178,12 +177,11 @@ namespace CodeImp.DoomBuilder.Map
 			t.flags = new Dictionary<string,bool>(flags);
 			t.tag = tag;
 			t.action = action;
-			t.args = EMPTY_ARGS;
+			t.args = (int[])args.Clone();
 			t.size = size;
 			t.color = color;
 			t.iconoffset = iconoffset;
 			t.fixedsize = fixedsize;
-			args.CopyTo(t.args, 0);
 			base.CopyPropertiesTo(t);
 		}