diff --git a/Source/Core/Windows/LinedefEditForm.cs b/Source/Core/Windows/LinedefEditForm.cs
index 8c7e0a8..f2939a1 100644
--- a/Source/Core/Windows/LinedefEditForm.cs
+++ b/Source/Core/Windows/LinedefEditForm.cs
@@ -482,27 +482,24 @@ namespace CodeImp.DoomBuilder.Windows
 				}
 
 				// (Re)set hacky flat alignment 
-				if (l.IsFlatAlignment || l.Action == 0)
+				if (sectortags.ContainsKey(l.Tag))
 				{
-					if (sectortags.ContainsKey(l.Tag))
+					foreach (Sector s in sectortags[l.Tag])
 					{
-						foreach (Sector s in sectortags[l.Tag])
-						{
-							s.UpdateFloorSurface();
-							s.UpdateCeilingSurface();
-						}
+						s.UpdateFloorSurface();
+						s.UpdateCeilingSurface();
 					}
-					if (oldtag != 0 && sectortags.ContainsKey(oldtag))
-					{
-						foreach (Sector s in sectortags[oldtag])
-						{
-							s.UpdateFloorSurface();
-							s.UpdateCeilingSurface();
-						}
-					}
-					l.Front.Sector.UpdateFloorSurface();
-					l.Front.Sector.UpdateCeilingSurface();
 				}
+				if (sectortags.ContainsKey(oldtag) && oldtag != l.Tag)
+				{
+					foreach (Sector s in sectortags[oldtag])
+					{
+						s.UpdateFloorSurface();
+						s.UpdateCeilingSurface();
+					}
+				}
+				l.Front.Sector.UpdateFloorSurface();
+				l.Front.Sector.UpdateCeilingSurface();
 			}
 
 			// Update the used textures
@@ -564,7 +561,24 @@ namespace CodeImp.DoomBuilder.Windows
                 LinedefActionInfo li = General.Map.Config.GetLinedefActionInfo(action.Value);
                 IDictionary<string, string> newFlags = (li == null || li.Flags.Count == 0) ? General.Map.Config.LinedefFlags : li.Flags;
                 flags.UpdateCheckboxes(newFlags);
-            }
+
+				// (Re)set hacky flat alignment 
+				foreach (Linedef l in lines)
+				{
+					if (l.Tag == 0)
+					{
+						l.Front.Sector.UpdateFloorSurface();
+						l.Front.Sector.UpdateCeilingSurface();
+					}
+					else
+						foreach (Sector s in General.Map.Map.Sectors)
+							if (s.Tag == l.Tag)
+							{
+								s.UpdateFloorSurface();
+								s.UpdateCeilingSurface();
+							}
+				}
+			}
 		}
 
 		// Browse Action clicked
@@ -611,6 +625,23 @@ namespace CodeImp.DoomBuilder.Windows
 						l.SetFlag(c.Tag.ToString(), false);
 				}
 
+				// (Re)set hacky flat alignment 
+				if (l.IsFlatAlignment)
+				{
+					if (l.Tag == 0)
+					{
+						l.Front.Sector.UpdateFloorSurface();
+						l.Front.Sector.UpdateCeilingSurface();
+					}
+					else
+						foreach (Sector s in General.Map.Map.Sectors)
+							if (s.Tag == l.Tag)
+							{
+								s.UpdateFloorSurface();
+								s.UpdateCeilingSurface();
+							}
+				}
+
 				i++;
 			}
 			
@@ -824,6 +855,23 @@ namespace CodeImp.DoomBuilder.Windows
 					}
 				}
 
+				// (Re)set hacky flat alignment 
+				if (l.IsFlatAlignment && l.IsFlagSet("8192"))
+				{
+					if (l.Tag == 0)
+					{
+						l.Front.Sector.UpdateFloorSurface();
+						l.Front.Sector.UpdateCeilingSurface();
+					}
+					else
+						foreach (Sector s in General.Map.Map.Sectors)
+							if (s.Tag == l.Tag)
+							{
+								s.UpdateFloorSurface();
+								s.UpdateCeilingSurface();
+							}
+				}
+
 				i++;
 			}