diff --git a/tools/cooja/java/org/contikios/cooja/plugins/LogListener.java b/tools/cooja/java/org/contikios/cooja/plugins/LogListener.java
index df2bf3cfc..b806906c3 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/LogListener.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/LogListener.java
@@ -383,6 +383,9 @@ public class LogListener extends VisPlugin implements HasQuickHelp {
         }
 
         int rowIndex = logTable.rowAtPoint(e.getPoint());
+        if (rowIndex == -1) {
+          return;
+        }
         LogData d = logs.get(logTable.getRowSorter().convertRowIndexToModel(rowIndex));
         if (d == null) {
         	return;