code: @Api
  	public void addButton(String layerId, ToolStripButton button, int position) {
  		extraButtons.add(new ExtraButton(constructIdSaveLayerId(layerId), button, position));
  	}
docs: Add a button in the tool strip at the requested position.
  
  @param layerId layer which needs the extra button
  @param button button to add
  @param position position