Fix KillcheckerVisualizer

Signed-off-by: yoyosource <yoyosource@nidido.de>

BauSystem_Main/src/de/steamwar/bausystem/features/killchecker/KillcheckerVisualizer.java

@@ -33,7 +33,10 @@ import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.entity.Player;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
 
 public class KillcheckerVisualizer {
 
@@ -207,7 +210,7 @@ public class KillcheckerVisualizer {
     public boolean hide(Player player) {
         rEntityServer.removePlayer(player);
         players.remove(player);
-        if (player.isEmpty()) {
+        if (players.isEmpty()) {
             rEntityServer.close();
             return true;
         }