diff --git a/commons/src/main/java/lcsb/mapviewer/common/comparator/LineComparator.java b/commons/src/main/java/lcsb/mapviewer/common/comparator/LineComparator.java
index f1942bd191f58774d497454dffeadc570b5ba025..cbf00430871d1ef70ddd8571e66a76ad2f184687 100644
--- a/commons/src/main/java/lcsb/mapviewer/common/comparator/LineComparator.java
+++ b/commons/src/main/java/lcsb/mapviewer/common/comparator/LineComparator.java
@@ -3,6 +3,8 @@ package lcsb.mapviewer.common.comparator;
 import java.awt.geom.Line2D;
 import java.util.Comparator;
 
+import org.apache.log4j.Logger;
+
 import lcsb.mapviewer.common.Configuration;
 
 /**
@@ -13,6 +15,8 @@ import lcsb.mapviewer.common.Configuration;
  */
 public class LineComparator implements Comparator<Line2D> {
 
+  private static Logger logger = Logger.getLogger(LineComparator.class);
+
   private PointComparator pointComparator;
 
   /**
@@ -45,8 +49,12 @@ public class LineComparator implements Comparator<Line2D> {
       return -1;
     }
     if (pointComparator.compare(arg0.getP1(), arg1.getP1()) != 0) {
+      logger.debug("Line start different: [" + arg0.getP1() + ", " + arg0.getP2() + "] - [" + arg1.getP1() + ", "
+          + arg1.getP2() + "]");
       return pointComparator.compare(arg0.getP1(), arg1.getP1());
     } else if (pointComparator.compare(arg0.getP2(), arg1.getP2()) != 0) {
+      logger.debug("Line end different: [" + arg0.getP1() + ", " + arg0.getP2() + "] - [" + arg1.getP1() + ", "
+          + arg1.getP2() + "]");
       return pointComparator.compare(arg0.getP2(), arg1.getP2());
     } else {
       return 0;
diff --git a/commons/src/main/java/lcsb/mapviewer/common/comparator/ListComparator.java b/commons/src/main/java/lcsb/mapviewer/common/comparator/ListComparator.java
index 1d7334ca267883ac1822cf93752ef3a7f0fbade3..ed362b8c58296b9d14994c03723a01175af0a0f7 100644
--- a/commons/src/main/java/lcsb/mapviewer/common/comparator/ListComparator.java
+++ b/commons/src/main/java/lcsb/mapviewer/common/comparator/ListComparator.java
@@ -15,7 +15,6 @@ public class ListComparator<T> implements Comparator<List<T>> {
   /**
    * Default class logger.
    */
-  @SuppressWarnings("unused")
   private Logger logger = Logger.getLogger(ListComparator.class);
 
   private Comparator<T> objectComparator;
@@ -37,6 +36,7 @@ public class ListComparator<T> implements Comparator<List<T>> {
     }
 
     if (arg0.size() != arg1.size()) {
+      logger.debug("Number of elements in list different: " + arg0.size() + ", " + arg1.size());
       return new IntegerComparator().compare(arg0.size(), arg1.size());
     }
     for (int i = 0; i < arg0.size(); i++) {