Does anyone know the difference "ESRI.ArcGIS.System" and "ESRI.ArcGIS.esriSystem" ?
The System library is the lowest level library in the ArcGIS architecture. The library contains components that expose services used by the other libraries composing ArcGIS.
The Display library contains the components that support drawing symbology to an output device. Screen displays, symbols, colors and feedback objects, along with their supporting objects are all defined in the library.