code: protected void addDecoration(Widget widget, int width, boolean first) {
  
          m_decorationWidgets.add(widget);
          m_decorationWidth += width;
      }
docs: Helper method for adding a decoration widget and updating the decoration width accordingly.<p>
  
  @param widget the decoration widget to add
  @param width the intended width of the decoration widget
  @param first if true, inserts the widget at the front of the decorations, else at the end.