***Get min or max value of control** - a sample plugin whose sources are located in *${GUI_ROOT_DIR}/share/salome/plugins/gui/demo* directory (files *minmax_plugin.py, minmax_ui.py and smesh_plugins.py*). You can find a detailed description of how to create your own plugin in documentation: **Help > User's Guide > GUI module > How-To's and Best Practices > Extend SALOME gui functions using python plugins**.