diff --git a/Source/Core/Map/Linedef.cs b/Source/Core/Map/Linedef.cs
index c3ab79b..14d2344 100644
--- a/Source/Core/Map/Linedef.cs
+++ b/Source/Core/Map/Linedef.cs
@@ -153,6 +153,9 @@ namespace CodeImp.DoomBuilder.Map
 				// Already set isdisposed so that changes can be prohibited
 				isdisposed = true;
 
+				if (map == General.Map.Map && General.Network != null && General.Network.ActionRunning)
+					General.Map.Map.RemovedElements.Add(this);
+
 				// Dispose sidedefs
 				if((front != null) && map.AutoRemove) front.Dispose(); else AttachFrontP(null);
 				if((back != null) && map.AutoRemove) back.Dispose(); else AttachBackP(null);
diff --git a/Source/Core/Map/MapSet.cs b/Source/Core/Map/MapSet.cs
index 463280a..e18fd09 100644
--- a/Source/Core/Map/MapSet.cs
+++ b/Source/Core/Map/MapSet.cs
@@ -163,6 +163,13 @@ namespace CodeImp.DoomBuilder.Map
 
 		internal bool AutoRemove { get { return autoremove; } set { autoremove = value; } }
 
+		public bool GeometryChanged { set; get; }
+
+		public bool PopulationChanged { set; get; }
+
+		/// <summary>List of all elements that were removed while the previous network action was running</summary>
+		public List<MapElement> RemovedElements { set; get; } = new List<MapElement>();
+
 		#endregion
 
 		#region ================== Constructor / Disposer
diff --git a/Source/Core/Map/Sector.cs b/Source/Core/Map/Sector.cs
index 772082a..6a10b78 100644
--- a/Source/Core/Map/Sector.cs
+++ b/Source/Core/Map/Sector.cs
@@ -175,6 +175,9 @@ namespace CodeImp.DoomBuilder.Map
 				// Already set isdisposed so that changes can be prohibited
 				isdisposed = true;
 				
+				if (map == General.Map.Map && General.Network != null && General.Network.ActionRunning)
+					General.Map.Map.RemovedElements.Add(this);
+
 				// Dispose the sidedefs that are attached to this sector
 				// because a sidedef cannot exist without reference to its sector.
 				if(map.AutoRemove)
diff --git a/Source/Core/Map/Sidedef.cs b/Source/Core/Map/Sidedef.cs
index 0712ac2..bbb7091 100644
--- a/Source/Core/Map/Sidedef.cs
+++ b/Source/Core/Map/Sidedef.cs
@@ -127,6 +127,9 @@ namespace CodeImp.DoomBuilder.Map
 				// Already set isdisposed so that changes can be prohibited
 				isdisposed = true;
 
+				if (map == General.Map.Map && General.Network != null && General.Network.ActionRunning)
+					General.Map.Map.RemovedElements.Add(this);
+
 				if(map == General.Map.Map)
 					General.Map.UndoRedo.RecRemSidedef(this);
 
diff --git a/Source/Core/Map/Thing.cs b/Source/Core/Map/Thing.cs
index d33cade..ceaa0c9 100644
--- a/Source/Core/Map/Thing.cs
+++ b/Source/Core/Map/Thing.cs
@@ -162,6 +162,9 @@ namespace CodeImp.DoomBuilder.Map
 			// Not already disposed?
 			if(!isdisposed)
 			{
+				if (map == General.Map.Map && General.Network != null && General.Network.ActionRunning)
+					General.Map.Map.RemovedElements.Add(this);
+
 				if(map == General.Map.Map)
 					General.Map.UndoRedo.RecRemThing(this);
 
diff --git a/Source/Core/Map/Vertex.cs b/Source/Core/Map/Vertex.cs
index 0bb6df1..bd14fed 100644
--- a/Source/Core/Map/Vertex.cs
+++ b/Source/Core/Map/Vertex.cs
@@ -118,6 +118,9 @@ namespace CodeImp.DoomBuilder.Map
 				// Already set isdisposed so that changes can be prohibited
 				isdisposed = true;
 
+				if (map == General.Map.Map && General.Network != null && General.Network.ActionRunning)
+					General.Map.Map.RemovedElements.Add(this);
+
 				if(map.AutoRemove)
 				{
 					// Dispose the lines that are attached to this vertex