Reference grid serves for better orientation in large drawings. It can be set using command
File - Options - Document - Reference Grid. You can specify along which edges the grid will be displayed. It is also possible to enable centering marks.
The area (sector) where the mouse pointer is located is shown in the status bar. It is also displayed in the list of wires for the ends of each wire.
The reference grid is available in the paid version of ProfiCAD only.