diff --git a/Build/Configurations/Includes/Boom_linedefs.cfg b/Build/Configurations/Includes/Boom_linedefs.cfg
index d1d25c9..9889467 100644
--- a/Build/Configurations/Includes/Boom_linedefs.cfg
+++ b/Build/Configurations/Includes/Boom_linedefs.cfg
@@ -107,7 +107,8 @@ floor
 	
 	213
 	{
-		title = "Floor Change Brightness to this Brightness";
+		title = "Change Floor Brightness to this Brightness";
+		id = "Boom_Transfer_FloorLight";
 		prefix = "";
 	}
 	
@@ -641,7 +642,8 @@ ceiling
 	
 	261
 	{
-		title = "Ceiling Brightness to this Brightness";
+		title = "Change Ceiling Brightness to this Brightness";
+		id = "Boom_Transfer_CeilingLight";
 		prefix = "";
 	}
 }
diff --git a/Build/Scripting/ZDoom_ACS.cfg b/Build/Scripting/ZDoom_ACS.cfg
index f339a31..fb0c47d 100644
--- a/Build/Scripting/ZDoom_ACS.cfg
+++ b/Build/Scripting/ZDoom_ACS.cfg
@@ -551,6 +551,7 @@ constants
 	APROP_Damage;
 	APROP_DamageFactor;
 	APROP_DamageMultiplier;
+	APROP_DamageType;
 	APROP_DeathSound;
 	APROP_Dormant;
 	APROP_Dropped;
diff --git a/Build/Scripting/ZDoom_DECORATE.cfg b/Build/Scripting/ZDoom_DECORATE.cfg
index 8f97916..dee5a20 100644
--- a/Build/Scripting/ZDoom_DECORATE.cfg
+++ b/Build/Scripting/ZDoom_DECORATE.cfg
@@ -1174,6 +1174,7 @@ constants
 	DMSS_EXFILTER;
 	DMSS_EXSPECIES;
 	DMSS_EITHER;
+	DMSS_INFLICTORDMGTYPE;
 	FMDF_NOPITCH;
 	FMDF_NOANGLE;
 	FMDF_INTERPOLATE;
diff --git a/Source/Core/Geometry/Tools.cs b/Source/Core/Geometry/Tools.cs
index 7917e28..8311da5 100644
--- a/Source/Core/Geometry/Tools.cs
+++ b/Source/Core/Geometry/Tools.cs
@@ -2327,8 +2327,12 @@ namespace CodeImp.DoomBuilder.Geometry
 				{
 					foreach(Linedef l in frontlines) 
 					{
-						l.FlipVertices();
-						l.FlipSidedefs();
+						// Skip single-sided lines with only front side
+						if(l.Back != null)
+						{
+							l.FlipVertices();
+							l.FlipSidedefs();
+						}
 					}
 				}
 			}
diff --git a/Source/Plugins/BuilderModes/ClassicModes/SectorsMode.cs b/Source/Plugins/BuilderModes/ClassicModes/SectorsMode.cs
index 66ec52e..f932cb8 100644
--- a/Source/Plugins/BuilderModes/ClassicModes/SectorsMode.cs
+++ b/Source/Plugins/BuilderModes/ClassicModes/SectorsMode.cs
@@ -2723,13 +2723,13 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			// Make undo
 			if(selected.Count > 1)
 			{
-				General.Map.UndoRedo.CreateUndo("Align linedefs of " + selected.Count + " sectors");
-				General.Interface.DisplayStatus(StatusType.Action, "Aligned linedefs of " + selected.Count + "sectors.");
+				General.Map.UndoRedo.CreateUndo("Flip linedefs of " + selected.Count + " sectors");
+				General.Interface.DisplayStatus(StatusType.Action, "Flipped linedefs of " + selected.Count + "sectors.");
 			}
 			else
 			{
-				General.Map.UndoRedo.CreateUndo("Align sector linedefs");
-				General.Interface.DisplayStatus(StatusType.Action, "Aligned sector linedefs.");
+				General.Map.UndoRedo.CreateUndo("Flip sector linedefs");
+				General.Interface.DisplayStatus(StatusType.Action, "Flipped sector linedefs.");
 			}
 
 			HashSet<Linedef> selectedlines = new HashSet<Linedef>();
@@ -2737,7 +2737,9 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			{
 				foreach(Sidedef side in s.Sidedefs)
 				{
-					if(!selectedlines.Contains(side.Line)) selectedlines.Add(side.Line);
+					// Skip single-sided lines with only front side
+					if(!selectedlines.Contains(side.Line) && (side.Line.Back != null || side.Line.Front == null))
+						selectedlines.Add(side.Line);
 				}
 			}