void savePrefs() {
        Properties prefs = new Properties();
        StringBuilder b = new StringBuilder();
        for (int i = 0; i < workCombo.getItemCount(); i++) {
            String dir = ((File) workCombo.getItemAt(i)).getPath();
            b.append(dir.replace('\\', '/'));
            if (i < workCombo.getItemCount() - 1) {
                b.append(";");
            }
        }
        prefs.setProperty(PREF_OPEN_FILES, b.toString());
        prefs.setProperty(PREF_ACTIVE_FILE, Integer.toString(workCombo.getSelectedIndex()));
        try {
            FileWriter w = new FileWriter(prefsFile);
            prefs.store(w, "OMS Preferences.");
            w.close();
        } catch (IOException ex) {
            Main.logger.log(Level.SEVERE, "Error", ex);
            ex.printStackTrace(System.err);
        }
    }