private void signalEditorSelectionChanged() {
        if(se_signal.getSelectionIndex() == -1) return;
        Contact contact = new Contact(se_signal.getText());
        Signal signal = signals.getSignals().get(contact);
        if(signal != null) {
            StringBuilder sb_time = new StringBuilder();
            StringBuilder sb_state = new StringBuilder();
            for(Long key : signal.getSignalSet().keySet()) {
                sb_time.append(key).append(' ');
                sb_state.append(signal.getState(key)).append(' ');
            }
            se_time.setText(sb_time.toString());
            se_state.setText(sb_state.toString());
        } else {
            se_time.setText("");
            se_state.setText("");
        }
    }