Added, Draw Lines mode: added "Remove First Vertex" action (Ctrl-Backspace). It removes the first drawn vertex from the drawing session. Renamed "Remove Previous Vertex" action to "Remove Last Vertex".

Changed, Classic modes: added a limit on how far the view can be scrolled from the editable map area.
Fixed, Drag geometry modes: in some cases incorrect vertices were removed when using "Replace with dragged geometry" drag mode.
Fixed, Game configurations: sector special 195 ("Hidden Sector") was missing from Hexen/UDMF specials list.

Build/Configurations/Includes/ZDoom_sectors.cfg

@@ -57,6 +57,7 @@ zdoom
 	115 = "Instant death";
 	116 = "Delayed damage strong (hazardcount +4/16 per second)";
 	118 = "Carry player by tag";
+	195 = "Hidden Sector (automap)";
 	196 = "Healing Sector";
 	197 = "Lightning Outdoor";
 	198 = "Lightning Indoor 2";

Source/Core/Editing/ClassicMode.cs

@@ -208,8 +208,11 @@ namespace CodeImp.DoomBuilder.Editing
 		// This scrolls anywhere
 		private void ScrollBy(float deltax, float deltay)
 		{
+			//mxd. Don't stroll too far from map boundaries
+			Vector2D offset = ClampViewOffset(renderer2d.OffsetX + deltax, renderer2d.OffsetY + deltay);
+
 			// Scroll now
-			renderer2d.PositionView(renderer2d.OffsetX + deltax, renderer2d.OffsetY + deltay);
+			renderer2d.PositionView(offset.x, offset.y);
 			this.OnViewChanged();
 			
 			// Redraw
@@ -265,9 +268,10 @@ namespace CodeImp.DoomBuilder.Editing
 
 			// Calculate view position difference
 			Vector2D diff = ((clientsize / newscale) - (clientsize / renderer2d.Scale)) * zoompos;
+			Vector2D offset = ClampViewOffset(renderer2d.OffsetX - diff.x, renderer2d.OffsetY + diff.y); //mxd
 
 			// Zoom now
-			renderer2d.PositionView(renderer2d.OffsetX - diff.x, renderer2d.OffsetY + diff.y);
+			renderer2d.PositionView(offset.x, offset.y);
 			renderer2d.ScaleView(newscale);
 			this.OnViewChanged();
 
@@ -281,6 +285,15 @@ namespace CodeImp.DoomBuilder.Editing
 			if(mouseinside) OnMouseMove(new MouseEventArgs(mousebuttons, 0, (int)mousepos.x, (int)mousepos.y, 0));
 		}
 
+		//mxd. Makes sure given offset stays within map boundaries
+		private static Vector2D ClampViewOffset(float x, float y)
+		{
+			Vector2D diff = new Vector2D(x, y);
+			Vector2D safediff = new Vector2D(General.Clamp(diff.x, General.Map.Config.LeftBoundary, General.Map.Config.RightBoundary),
+											 General.Clamp(diff.y, General.Map.Config.BottomBoundary, General.Map.Config.TopBoundary));
+			return diff - (diff - safediff);
+		}
+
 		//mxd. This changes current grid size based on current zoom level
 		internal void MatchGridSizeToDisplayScale()
 		{
@@ -659,7 +672,7 @@ namespace CodeImp.DoomBuilder.Editing
 				if(General.Settings.GZSynchCameras && !General.Interface.CtrlState 
 					&& General.Editing.PreviousMode != null && General.Editing.PreviousMode.IsSubclassOf(typeof(VisualMode)))
 				{
-					Vector2D campos = new Vector2D(General.Map.VisualCamera.Position.x, General.Map.VisualCamera.Position.y);
+					Vector2D campos = ClampViewOffset(General.Map.VisualCamera.Position.x, General.Map.VisualCamera.Position.y);
 					renderer2d.PositionView(campos.x, campos.y);
 				}
 

Source/Core/Map/MapSet.cs

@@ -2122,22 +2122,11 @@ namespace CodeImp.DoomBuilder.Map
 			//mxd. Remove remaining new verts from dragged shape if possible
 			if(mergemode == MergeGeometryMode.REPLACE)
 			{
-				// Get lines, which belong to dragged sectors
+				// Collect verts created by splitting. Can't use GetMarkedVertices here, because we are in the middle of AddRemove
-				HashSet<Sector> draggedsectors = GetSectorsFromLinedefs(movinglines);
-				HashSet<Linedef> sectorlines = new HashSet<Linedef>();
-				foreach(Sector s in draggedsectors)
-				{
-					foreach(Sidedef side in s.Sidedefs)
-						sectorlines.Add(side.Line);
-				}
-
 				HashSet<Vertex> tocheck = new HashSet<Vertex>();
-
+				foreach(Vertex v in vertices)
-				foreach(Linedef l in sectorlines)
 				{
-					if(l.IsDisposed) continue;
+					if(v != null && v.Marked && !movingverts.Contains(v)) tocheck.Add(v);
-					if(!movingverts.Contains(l.Start)) tocheck.Add(l.Start);
-					if(!movingverts.Contains(l.End)) tocheck.Add(l.End);
 				}
 
 				// Remove verts, which are not part of initially dragged verts

Source/Plugins/BuilderModes/ClassicModes/DrawGeometryMode.cs

@@ -943,15 +943,22 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			}
 		}
 		
-		// Remove a point
+		// Remove last point
 		[BeginAction("removepoint")]
-		public virtual void RemovePoint()
+		public virtual void RemovePoint() { RemovePointAt(points.Count - 1); }
+
+		//mxd. Remove first point 
+		[BeginAction("removefirstpoint")]
+		public virtual void RemoveFirstPoint() { RemovePointAt(0); }
+
+		//mxd
+		private void RemovePointAt(int index)
 		{
-			if(points.Count > 0) points.RemoveAt(points.Count - 1);
+			if(points.Count > 0 && points.Count > index) points.RemoveAt(index);
-			if(labels.Count > 0)
+			if(labels.Count > 0 && labels.Count > index)
 			{
-				labels[labels.Count - 1].Dispose();
+				labels[index].Dispose();
-				labels.RemoveAt(labels.Count - 1);
+				labels.RemoveAt(index);
 			}
 			
 			Update();

Source/Plugins/BuilderModes/ClassicModes/DrawRectangleMode.cs

@@ -381,6 +381,11 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			Update();
 		}
 
+		public override void RemoveFirstPoint()
+		{
+			RemovePoint();
+		}
+
 		#endregion
 
 		#region ================== Events

Source/Plugins/BuilderModes/Resources/Actions.cfg

@@ -323,14 +323,25 @@ drawpoint
 
 removepoint
 {
-	title = "Remove Previous Vertex";
+	title = "Remove Last Vertex";
 	category = "drawing";
-	description = "Removes the previously drawn vertex from the drawing session.";
+	description = "Removes the last drawn vertex from the drawing session.";
 	allowkeys = true;
 	allowmouse = true;
 	allowscroll = true;
 }
 
+removefirstpoint
+{
+	title = "Remove First Vertex";
+	category = "drawing";
+	description = "Removes the first drawn vertex from the drawing session.";
+	allowkeys = true;
+	allowmouse = true;
+	allowscroll = true;
+	default = 131080; // Ctrl-Backspace
+}
+
 finishdraw
 {
 	title = "Finish Drawing";