warningThresholdField.addFocusListener(this);
thresholdPanel.add(warningThresholdField);
assertionPanel.add(thresholdPanel);
//file panel
filePanel = new FilePanel(JMeterUtils.getResString("file_visualizer_output_file"), ".txt");
filePanel.addChangeListener(this);
assertionPanel.add(filePanel);
mainPanel.add(assertionPanel, BorderLayout.NORTH);
add(mainPanel, BorderLayout.CENTER);