/** \page uiconcept "User Interface Concepts"
 *
 * The OpenFlipper user interface is composed of 4 essential widgets
 * each accessible and extendable by user plugins:
 *
 * -\ref viewport_widget
 * -\ref plugin_widget
 * -\ref logging_widget
 * -\ref tool_bar
 *
 * \subsection viewport_widget The viewport widget
 *
 * 
 *
 * \subsection plugin_widget The plugin widget
 * \subsection logging_widget The logging widget
 * \subsection tool_bar The tool bar
 */