JComboBox is not visible on JPanel

Question

I have a class that extends JPanel. Within this class I have added several different components; JLabels, JTextFields, JButtons and a JComboBox.
All of the added components are visible and working except for the JComboBox. I can see the white background of the box and the popup and its list when I click on the area where the JComboBox is located, but I cannot see the selected text in the box. This seems strange since all the other components surrounding the JComboBox display correctly.
The background is set to white and the foreground is set to black. It has three options in the popup which are displayed using the foreground color, as it should. When I select an option from the popup, it seems to be working because the next time I display the popup, that selection is highlighted. But the selected text never shows in the box.
If I create a JComboBox in a JPanel, not an extended class, everything seems to work correctly. I can select from the popup and the selection appears in the box.
Could you please give me some suggestions as to how to make the selected text in the JComboBox visible?
Thanks
Bob

Answer 1

My layout manager is set to null. I don't think that there is anything obscuring it because the backgroud is visible. The only thing that I can't see it the selected text and the combo box down arrow. I am using VisualCafe to generate this code.
The extended class is loaded from the following class:
public class TheSchedule extends javax.swing.JFrame
using the following code:
     void JButtonGenTimeUnits_actionPerformed(java.awt.event.ActionEvent event)
          JPanelMainPanel.add(new TimeUnitDefinition((Frame)this));
          JPanelMainPanel.repaint();
The actual code of the TimeUnitDefinition is as follows:
package com.klawuhn.schedule;
import javax.swing.*;
import java.beans.*;
import java.awt.*;
import com.symantec.itools.javax.swing.models.StringComboBoxModel;
import symantec.itools.awt.util.Calendar;
import com.symantec.itools.javax.swing.borders.LineBorder;
public class TimeUnitDefinition extends javax.swing.JPanel {
private Frame parentFrame = null;
     public TimeUnitDefinition(Frame parentFrame)
     this.parentFrame = parentFrame; // Needed when displaying the calendars
          //{{INIT_CONTROLS
          setAlignmentY(1.0F);
          setAlignmentX(1.0F);
          setOpaque(false);
          setLayout(null);
          setSize(457,283);
          JLabelStartDate.setText("Start Date:");
          add(JLabelStartDate);
          JLabelStartDate.setBounds(12,12,156,24);
          JTextFieldStartDate.setDisabledTextColor(java.awt.Color.white);
          JTextFieldStartDate.setToolTipText("This is the date to start generating time units.");
          JTextFieldStartDate.setEditable(false);
          add(JTextFieldStartDate);
          JTextFieldStartDate.setBackground(java.awt.Color.white);
          JTextFieldStartDate.setBounds(168,12,216,24);
          JButtonCalendar1.setText("-");
          JButtonCalendar1.setActionCommand("-");
          add(JButtonCalendar1);
          JButtonCalendar1.setBounds(384,12,24,24);
          JLabelEndDate.setText("End Date:");
          add(JLabelEndDate);
          JLabelEndDate.setBackground(java.awt.Color.cyan);
          JLabelEndDate.setBounds(12,48,156,24);
          JTextFieldEndDate.setDisabledTextColor(java.awt.Color.white);
          JTextFieldEndDate.setToolTipText("This is the date to start generating time units.");
          JTextFieldEndDate.setEditable(false);
          add(JTextFieldEndDate);
          JTextFieldEndDate.setBackground(java.awt.Color.white);
          JTextFieldEndDate.setBounds(168,48,216,24);
          JButtonCalendar2.setText("-");
          JButtonCalendar2.setActionCommand("-");
          add(JButtonCalendar2);
          JButtonCalendar2.setBounds(384,48,24,24);
          JLabelStartTime.setText("Start Time:");
          add(JLabelStartTime);
          JLabelStartTime.setBounds(12,84,156,24);
          JTextFieldStartTime.setToolTipText("This is the time of day to start generating time units.");
          add(JTextFieldStartTime);
          JTextFieldStartTime.setBounds(168,84,240,24);
          JLabelEndTime.setText("End Time:");
          add(JLabelEndTime);
          JLabelEndTime.setBounds(12,120,156,24);
          JTextFieldEndTime.setToolTipText("This is the time of day to end generating time units.");
          add(JTextFieldEndTime);
          JTextFieldEndTime.setBounds(168,120,240,24);
          JLabelUnitOfMeasure.setText("Unit of Measure:");
          add(JLabelUnitOfMeasure);
          JLabelUnitOfMeasure.setBounds(12,156,156,24);
          JComboBoxUnitOfMeasure.setModel(stringComboBoxModel1);
          JComboBoxUnitOfMeasure.setToolTipText("This is the unit of measure used when generating the time units.");
          add(JComboBoxUnitOfMeasure);
          JComboBoxUnitOfMeasure.setBackground(java.awt.Color.white);
          JComboBoxUnitOfMeasure.setForeground(java.awt.Color.black);
          JComboBoxUnitOfMeasure.setBounds(168,156,240,24);
          JLabelBlockSize.setText("Block Size:");
          add(JLabelBlockSize);
          JLabelBlockSize.setBounds(12,192,156,24);
          JTextFieldBlockSize.setText("45");
          JTextFieldBlockSize.setToolTipText("This is the size of the time unit in Unit of Measures.");
          add(JTextFieldBlockSize);
          JTextFieldBlockSize.setBounds(168,192,240,24);
          JButtonSubmit.setText("Submit");
          JButtonSubmit.setActionCommand("Submit");
          JButtonSubmit.setToolTipText("This button will generate the time units.");
          add(JButtonSubmit);
          JButtonSubmit.setBounds(36,228,108,40);
          JButtonCancel.setText("Cancel");
          JButtonCancel.setActionCommand("Cancel");
          JButtonCancel.setToolTipText("This button will discard any changes.");
          add(JButtonCancel);
          JButtonCancel.setBounds(288,228,108,40);
               String[] tempString = new String[3];
               tempString[0] = "Days";
               tempString[1] = "Hours";
               tempString[2] = "Minutes";
               stringComboBoxModel1.setItems(tempString);
          //$$ stringComboBoxModel1.move(0,288);
          JComboBoxUnitOfMeasure.setSelectedIndex(2);
          //{{REGISTER_LISTENERS
          SymAction lSymAction = new SymAction();
          JButtonSubmit.addActionListener(lSymAction);
          JButtonCalendar1.addActionListener(lSymAction);
          JButtonCalendar2.addActionListener(lSymAction);
     //{{DECLARE_CONTROLS
     javax.swing.JLabel JLabelStartDate = new javax.swing.JLabel();
     javax.swing.JTextField JTextFieldStartDate = new javax.swing.JTextField();
     javax.swing.JButton JButtonCalendar1 = new javax.swing.JButton();
     javax.swing.JLabel JLabelEndDate = new javax.swing.JLabel();
     javax.swing.JTextField JTextFieldEndDate = new javax.swing.JTextField();
     javax.swing.JButton JButtonCalendar2 = new javax.swing.JButton();
     javax.swing.JLabel JLabelStartTime = new javax.swing.JLabel();
     javax.swing.JTextField JTextFieldStartTime = new javax.swing.JTextField();
     javax.swing.JLabel JLabelEndTime = new javax.swing.JLabel();
     javax.swing.JTextField JTextFieldEndTime = new javax.swing.JTextField();
     javax.swing.JLabel JLabelUnitOfMeasure = new javax.swing.JLabel();
     javax.swing.JComboBox JComboBoxUnitOfMeasure = new javax.swing.JComboBox();
     javax.swing.JLabel JLabelBlockSize = new javax.swing.JLabel();
     javax.swing.JTextField JTextFieldBlockSize = new javax.swing.JTextField();
     javax.swing.JButton JButtonSubmit = new javax.swing.JButton();
     javax.swing.JButton JButtonCancel = new javax.swing.JButton();
     com.symantec.itools.javax.swing.models.StringComboBoxModel stringComboBoxModel1 = new com.symantec.itools.javax.swing.models.StringComboBoxModel();
     class SymAction implements java.awt.event.ActionListener
          public void actionPerformed(java.awt.event.ActionEvent event)
               Object object = event.getSource();
               if (object == JButtonSubmit)
                    JButtonSubmit_actionPerformed(event);
               else if (object == JButtonCalendar1)
                    JButtonCalendar1_actionPerformed(event);
               else if (object == JButtonCalendar2)
                    JButtonCalendar2_actionPerformed(event);
     void JButtonSubmit_actionPerformed(java.awt.event.ActionEvent event)
          System.out.println("See Submit button");
          TimeUnitCreate timeUnitCreate = new TimeUnitCreate(
          JTextFieldStartDate.getText(),
          JTextFieldEndDate.getText(),
          JTextFieldStartTime.getText(),
          JTextFieldEndTime.getText(),
          (String)JComboBoxUnitOfMeasure.getSelectedItem(),
          JTextFieldBlockSize.getText()
          timeUnitCreate.createTimeUnits();
          this.setVisible(false);
System.out.println("Done creating Time Units.");
// (new TimeUnitDefinition()).setVisible(true);
     void JButtonCalendar1_actionPerformed(java.awt.event.ActionEvent event)
     CalendarDialog calendarDialog = new CalendarDialog(parentFrame,"Date",true);
     calendarDialog.show();
     JTextFieldStartDate.setText(calendarDialog.getSelectedDate());
     void JButtonCalendar2_actionPerformed(java.awt.event.ActionEvent event)
     CalendarDialog calendarDialog = new CalendarDialog(parentFrame,"Date",true);
     calendarDialog.show();
     JTextFieldEndDate.setText(calendarDialog.getSelectedDate());
}