code: protected void addDecoration (JDecoration decoration) {
  		if (m_jDecorations == null) {
  			m_jDecorations = new Vector();
  		}
  		if (!m_jDecorations.contains(decoration)) {
  			decoration.setStaffLine(getStaffLine());
  			m_jDecorations.add(decoration);
  		}
  	}
docs: Add decoration if it hasn't been added previously