warningThresholdField.addKeyListener(this);
thresholdPanel.add(warningThresholdField);
assertionPanel.add(thresholdPanel);
// file panel
filePanel = new FilePanel(JMeterUtils.getResString("html_assertion_file"), ".txt"); //$NON-NLS-1$ //$NON-NLS-2$
assertionPanel.add(filePanel);
mainPanel.add(assertionPanel, BorderLayout.NORTH);
add(mainPanel, BorderLayout.CENTER);
}