Add action for removing FOF planes from Visual Mode selection

Source/Plugins/BuilderModes/Resources/Actions.cfg

@@ -1376,6 +1376,16 @@ alphabasedtexturehighlighting
 	allowscroll = true;	
 }
 
+deselectfofplanes
+{
+	title = "Deselect FOF planes";
+	category = "visual";
+	description = "Deselects all FOF planes from your selection in Visual Mode.";
+	allowkeys = true;
+	allowmouse = true;
+	allowscroll = true;	
+}
+
 placevisualstart
 {
 	title = "Place Visual Mode Camera";

Source/Plugins/BuilderModes/VisualModes/BaseVisualGeometrySector.cs

@@ -1058,6 +1058,20 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			}
 		}
 
+		public void OnRemoveFOFSelection()
+		{
+			if (level != null)
+			{
+				// This plane is part of a 3D-floor/FOF
+				if (level.sector != Sector.Sector)
+				{
+					BaseVisualSector vs = (BaseVisualSector)mode.GetVisualSector(level.sector);
+					selected = false;
+					mode.RemoveSelectedObject(this);
+				}
+			}
+		}
+
 		#endregion
 	}
 }

Source/Plugins/BuilderModes/VisualModes/BaseVisualMode.cs

@@ -4460,6 +4460,32 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			General.Interface.DisplayStatus(StatusType.Info, "Alpha-based textures highlighting is " + (BuilderPlug.Me.AlphaBasedTextureHighlighting ? "ENABLED" : "DISABLED"));
 		}
 
+		[BeginAction("deselectfofplanes")]
+		public void DeselectFOFPlanes()
+		{
+			PreAction(UndoGroup.None);
+			List<IVisualEventReceiver> objs = GetSelectedObjects(true, false, false, false);
+
+			foreach (IVisualEventReceiver i in objs)
+			{
+				if (i is VisualFloor)
+				{
+					VisualFloor vf = i as VisualFloor;
+					vf.OnRemoveFOFSelection();
+				}
+
+				if (i is VisualCeiling)
+				{
+					VisualCeiling vc = i as VisualCeiling;
+					vc.OnRemoveFOFSelection();
+				}
+			}
+
+			General.Interface.DisplayStatus(StatusType.Action, "Deselected FOF planes.");
+			General.Interface.RedrawDisplay();
+			UpdateSelectionInfo();
+			UpdateChangedObjects();
+		}
 		#endregion
 
 		#region ================== Texture Alignment