firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);
firePropertyChange(PROP_ASSOCIATED_COLUMNS, null, null);