This option is used to give feedback on the status bar of the current location of the mouse. It is set to either be on or off and it is a global setting across all Map Windows.
If the mouse is outside of the data extents, it will show both the current position in lon/lat and in the coordinates of the currently selected projection. Note that the format of the lon/lat can be controlled via the "Status bar shows DMS" option in the Global Settings.
If the cursor is within the data extents, the cursor message box will display additional information. In addition to what is shown above, the cursor message box will display the interpolated measurement value at the cursor location, the nearest measurement point location lon/lat, the name of the measurement point (not shown for gridded images), the measurement point type and the measurement value of the nearest point.
