Unwanted ListSelectionEvent when using JComboBox

Edited text of question

Edited text of question

What does the combo box have to do with the table? Why selecting an item from the combo box should have any bearing on the table model? It is not very clear.

When using System.out.println(LSe.getSource()); (where LSe is a ListSelectionEvent) the event looks like this com.sun.java.swing.event.ListSelectionEvent[ source=com.sun.java.swing.DefaultListSelectionModel 1898706 ={} firstIndex= 0 lastIndex= -1 isAdjusting= false ].
Thus, if I don't set the adjusting to true from the choice in the JComboBox your suggstion will never work, won't it?

I never worked with the adjusting property so I don't know how to set.
What must I do to set adjusting true and where or when?

For msmolyak:
In the JComboBox all the portfolios of a user are listed.
When starting the JApplet all portfolio names will be added and all portfolio data will be displayed. However, if the portfolios contain a large number of entries a user might want to see only one of his, say ten, portfolios. Then he simply needs to make a choice in the JComboBox and only the values of the selected portfolio will be displayed.
This is the need for the JComboBox related to the JTable in this JApplet.

I found a method in JTable called setValueIsAdjusting. Do I understand the explanation right that its function is like removing a listener object and after handling the event use the addXXXListener method?

I tried out what you suggested but it doesn't take any effect. However, my problem seems to be nonexistent anymore (wether using setValueIsAdjusting or not).

Maybe you could answer me another questions that I can grade you? Hope this is OK?

In my JApplet I read some data from a database and I use a DefaultTableModel to store the values in a Vecotr of Vectors.
Here's the code which is used to store the data from the ResultSet into the Vecotrs:

            try
            {
                  if( queryResult == null)
                  {
                        System.err.println("ResultSet geschlossen.");
                        return false;
                  }

                  ResultSetMetaData rsmd = queryResult.getMetaData();
                  int columns = rsmd.getColumnCount();
                  
                  columnNames = new Vector(columns);
                  for(int i=0; i<columns; i++)
                  {
                        columnNames.addElement(rsmd.getColumnLabel(i+1));
                        System.out.println(columnNames.elementAt(i).toString());
                  }

                  rows = new Vector();
                  while( queryResult.next() )
                  {
                        Vector cols = new Vector(columns);
                        for(int i=1; i<=columns; i++)
                        {
                              int type = rsmd.getColumnType(i);
                              cols.addElement(readValue(queryResult, type, i));
                        }
                        rows.addElement(cols);
                  }//end while( queryResult.next() )


      protected final Object readValue(ResultSet queryResult, int type, int col)
      {
            Object value = null;

            try
            {
                  switch(type)
                  {
                        case Types.CHAR:
                        case Types.VARCHAR:
                        case Types.LONGVARCHAR:
                                                            value = queryResult.getString(col).trim();
                                                            break;
                        case Types.BIT:
                                                            Boolean bool = new Boolean(queryResult.getBoolean(col));
                                                            value = bool;
                                                            break;
                        case Types.TINYINT:
                        case Types.SMALLINT:
                        case Types.INTEGER:
                                                            Integer num = new Integer(queryResult.getString(col));
                                                            value = num;
                                                            break;
                        case Types.BIGINT:
                                                            Long numL = new Long(queryResult.getString(col));
                                                            value = numL;
                                                            break;
                        case Types.REAL:
                                                            Float real = new Float(queryResult.getString(col));
                                                            value = real;
                                                            break;
                        case Types.FLOAT:
                        case Types.DOUBLE:
                                                            Double dbl = new Double(queryResult.getString(col));
                                                            value = dbl;
                                                            break;
                        case Types.NUMERIC:
                        case Types.DECIMAL:
                                                            BigDecimal bDec;
                                                            bDec = new BigDecimal(queryResult.getString(col));
                                                            bDec.setScale(precision);
                                                            value = bDec;
                                                            break;
                        case Types.DATE:
                                                            value = queryResult.getDate(col);
                                                            break;
                        case Types.TIME:
                                                            value = queryResult.getTime(col);
                                                            break;
                        case Types.TIMESTAMP:
                                                            value = queryResult.getTimestamp(col);
                                                            break;
                        case Types.BINARY:
                        case Types.VARBINARY:
                        case Types.LONGVARBINARY:
                                                            value = queryResult.getBytes(col);
                                                            break;
                        default:            value = queryResult.getObject(col);
                  }//end switch
                  return value;
            }
            catch(SQLException SQLe)
            {
                  System.err.println("SQL-Fehler: " + SQLe.toString());
                  return null;
            }
      }//end readValue

This works really well. As you can see I set the scale of the BigDecimals to 2 before storing them into the Vector.
The problem:
When reading BigDecimal values from the Vector they ever have a scale of 4! I don't understand this.
Furthermore I do some calculations with the values in the table and add some further columns to the table in which the calculated values are placed. The calculated values have a scale of 4, too, even although I set the scale explicitely to 2.
After calculating I store the values in the Vector so that they can be shown in the table, of course.

So, how can I accomplish that BigDecimals are shown in the table with a scale/precision of 2?

Oops! The variable "precision" needs to be substituted with the value 2, of course. The int variable precision is set to 2 when I declare it in the class. besides there is a setPrecision(int val) in the class.