setImageDescriptor(JavaPluginImages.DESC_TOOL_SHOW_SEGMENTS);
JavaPluginImages.setImageDescriptors(this, "tool16", "segment_edit.gif");
	public TogglePresentationAction(ResourceBundle bundle, String prefix) {		super(bundle, prefix, null);		setImageDescriptor(JavaPluginImages.DESC_TOOL_SHOW_SEGMENTS);		update();	}