Fixed, Linedefs mode: linedef selection labels must be updated when performing undo/redo.

Fixed, Things mode: thing selection labels must be updated when performing undo/redo.
Fixed another case of invalid sectors being created after dragging map elements when using "Merge Dragged Geometry" and "Replace with Dragged Geometry" drag modes.

Source/Core/Geometry/Tools.cs

@@ -2407,22 +2407,21 @@ namespace CodeImp.DoomBuilder.Geometry
 		{
 			List<LinedefSide> sectorsides = FindPotentialSectorAt(line, front);
 			if(sectorsides == null) return null;
-			Sector result = null;
-			bool foundstartline = false;
 
-			// Proceed only if all sectorsides reference the same sector and the start line is among them
+			// Check potential sectors
 			foreach(LinedefSide sectorside in sectorsides)
 			{
 				Sidedef target = (sectorside.Front ? sectorside.Line.Front : sectorside.Line.Back);
-				if(target == null) return null; // Fial...
-				
-				if(result == null) result = target.Sector;
-				else if(result != target.Sector) return null; // Fial...
-
-				if(sectorside.Line == line) foundstartline = true;
+				if(target != null && target.Sector != null)
+				{
+					// Check if target line is inside the found sector
+					if(target.Sector.Intersect(line.Start.Position, false) && target.Sector.Intersect(line.End.Position, false))
+						return target.Sector;
+				}
 			}
 
-			return (foundstartline ? result : null);
+			// No dice...
+			return null;
 		}
 
 		#endregion

Source/Core/Map/Sector.cs

@@ -125,7 +125,7 @@ namespace CodeImp.DoomBuilder.Map
 		public FlatVertex[] FlatVertices { get { return flatvertices; } }
 		public ReadOnlyCollection<LabelPositionInfo> Labels { get { return labels; } }
 
-        //mxd. Rednering
+        //mxd. Rendering
         public Color4 FogColor { get { return fogcolor; } }
         public SectorFogMode FogMode { get { return fogmode; } }
 
@@ -534,7 +534,8 @@ namespace CodeImp.DoomBuilder.Map
 		
 		// This checks if the given point is inside the sector polygon
 		// See: http://paulbourke.net/geometry/polygonmesh/index.html#insidepoly
-		public bool Intersect(Vector2D p) 
+		public bool Intersect(Vector2D p) { return Intersect(p, true); }
+		public bool Intersect(Vector2D p, bool countontopastrue)
 		{
 			//mxd. Check bounding box first
 			if(p.x < bbox.Left || p.x > bbox.Right || p.y < bbox.Top || p.y > bbox.Bottom) return false;
@@ -550,7 +551,7 @@ namespace CodeImp.DoomBuilder.Map
 				v2 = sd.Line.End.Position;
 
 				//mxd. On top of a vertex?
-				if(p == v1 || p == v2) return true;
+				if(p == v1 || p == v2) return countontopastrue;
 
 				// Check for intersection
 				if(v1.y != v2.y //mxd. If line is not horizontal...

Source/Plugins/BuilderModes/ClassicModes/LinedefsMode.cs

@@ -943,7 +943,9 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		{
 			base.OnUndoEnd();
 
-			SetupSectorLabels(); // Update sector labels
+			// Update selection info and labels
+			UpdateSelectionInfo();
+			SetupSectorLabels();
 		}
 
 		//mxd
@@ -951,7 +953,9 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		{
 			base.OnRedoEnd();
 
-			SetupSectorLabels(); // Update sector labels
+			// Update selection info and labels
+			UpdateSelectionInfo();
+			SetupSectorLabels();
 		}
 
 		// Mouse moves

Source/Plugins/BuilderModes/ClassicModes/ThingsMode.cs

@@ -588,6 +588,7 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		{
 			base.OnUndoEnd();
 
+			UpdateSelectionInfo(); // Update selection info and labels
 			UpdateHelperObjects(); // Update helper lines
 			SetupSectorLabels(); // And sector labels
 		}
@@ -597,6 +598,7 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		{
 			base.OnRedoEnd();
 
+			UpdateSelectionInfo(); // Update selection info and labels
 			UpdateHelperObjects(); // Update helper lines
 			SetupSectorLabels(); // And sector labels
 		}