diff --git a/BauSystem_Main/src/de/steamwar/bausystem/BauSystem.java b/BauSystem_Main/src/de/steamwar/bausystem/BauSystem.java
index 565f368f..1d1e6362 100644
--- a/BauSystem_Main/src/de/steamwar/bausystem/BauSystem.java
+++ b/BauSystem_Main/src/de/steamwar/bausystem/BauSystem.java
@@ -121,19 +121,4 @@ public class BauSystem extends JavaPlugin implements Listener {
             }
         }));
     }
-
-    private void createLink(String source, String destination) {
-        try {
-            Bukkit.getLogger().log(Level.INFO, "Executing: ln -s /home/minecraft/server/Bau15/{0} {1}", new String[]{source, destination});
-            ProcessBuilder processBuilder = new ProcessBuilder("ln", "-s", "/home/minecraft/server/Bau15/" + source, destination);
-            processBuilder.directory(world.getWorldFolder());
-            processBuilder.inheritIO();
-
-            Process process = processBuilder.start();
-            process.waitFor();
-        } catch (IOException | InterruptedException e) {
-            Thread.currentThread().interrupt();
-            Bukkit.shutdown();
-        }
-    }
 }
\ No newline at end of file
diff --git a/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/EntityShowMode.java b/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/EntityShowMode.java
index 0dcf1187..62eb765d 100644
--- a/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/EntityShowMode.java
+++ b/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/EntityShowMode.java
@@ -113,8 +113,10 @@ public class EntityShowMode implements ShowMode<TNTPosition> {
         tntEntityMap.clear();
         explodeEntityMap.clear();
         updateEntityMap.clear();
-        entityServer.close();
-        entityServer = null;
+        if (entityServer != null) {
+            entityServer.close();
+            entityServer = null;
+        }
     }
 
     private void generatePositions(TNTPosition position, boolean interpolateY, boolean interpolateXZ) {
diff --git a/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/ShowModeParameter.java b/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/ShowModeParameter.java
index 2544a28b..d8e3a75f 100644
--- a/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/ShowModeParameter.java
+++ b/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/ShowModeParameter.java
@@ -29,8 +29,8 @@ public class ShowModeParameter {
     private boolean sourceOnly = false;
     private boolean explodeOnly = false;
     private boolean ticks = false;
-    private boolean buildDestroyOnly = false;
     private boolean count = false;
+    private boolean buildDestroyOnly = false;
 
     public void enableWater() {
         this.water = true;
@@ -56,11 +56,11 @@ public class ShowModeParameter {
         this.ticks = true;
     }
 
-    public void enableBuildDestroyOnly() {
-        this.buildDestroyOnly = true;
-    }
-
     public void enableCount() {
         this.count = true;
     }
+
+    public void enableBuildDestroyOnly() {
+        this.buildDestroyOnly = true;
+    }
 }
diff --git a/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/TraceShowManager.java b/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/TraceShowManager.java
index 82ca5673..856513ff 100644
--- a/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/TraceShowManager.java
+++ b/BauSystem_Main/src/de/steamwar/bausystem/features/tracer/show/TraceShowManager.java
@@ -63,7 +63,7 @@ public class TraceShowManager implements Listener {
         if (regionalShowModes == null) {
             return;
         }
-        ShowMode<TNTPosition> showMode = regionalShowModes.get(player);
+        ShowMode<TNTPosition> showMode = regionalShowModes.remove(player);
         if (showMode == null) {
             return;
         }
@@ -160,13 +160,10 @@ public class TraceShowManager implements Listener {
 
     @EventHandler
     public void onLeave(PlayerQuitEvent event) {
-        Region region = Region.getRegion(event.getPlayer().getLocation());
-        if (!region.isGlobal()) {
-            Map<Player, ShowMode<TNTPosition>> regionalShowModes = showModes.get(region);
-            if (regionalShowModes != null) {
-                regionalShowModes.remove(event.getPlayer()).hide();
-            }
-        }
+        showModes.forEach((region, playerShowModeMap) -> {
+            ShowMode<TNTPosition> showMode = playerShowModeMap.remove(event.getPlayer());
+            if (showMode != null) showMode.hide();
+        });
         StoredRecords.cleanup(event.getPlayer());
     }
 }
diff --git a/BauSystem_Main/src/de/steamwar/bausystem/utils/RayTraceUtils.java b/BauSystem_Main/src/de/steamwar/bausystem/utils/RayTraceUtils.java
index 2145e442..463820f7 100644
--- a/BauSystem_Main/src/de/steamwar/bausystem/utils/RayTraceUtils.java
+++ b/BauSystem_Main/src/de/steamwar/bausystem/utils/RayTraceUtils.java
@@ -71,4 +71,18 @@ public class RayTraceUtils {
             return entityHitDistanceSquared < blockHitDistance * blockHitDistance ? entities : blocks;
         }
     }
+
+    public static boolean isOccluded(Vector a, Vector n, Vector b) {
+        // a = Head pos, n = View direction (normalized), b = entity center
+        // https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line#Vector_formulation
+
+        double abX = b.getX() - a.getX();
+        double abY = b.getY() - a.getY();
+        double abZ = b.getZ() - a.getZ();
+        double lambda = abX * n.getX() + abY * n.getY() + abZ * n.getZ();
+        double distX = abX - n.getX() * lambda;
+        double distY = abY - n.getY() * lambda;
+        double distZ = abZ - n.getZ() * lambda;
+        return Math.abs(distX) < 0.5 && Math.abs(distY) < 0.5 && Math.abs(distZ) < 0.5;
+    }
 }