NEC KT-X46UN User Manual page 27

The main area in the window shows a visual representation of the current video wall layout. Each rectangle
represents a display. The color of the rectangle shows the current status of a particular display. This coloring
makes it easy to see the status even when viewing from a distance.
Within each rectangle the displays sequence number is shown. This number is used to identify each display, and
the number ordering represents the order in which displays will be measured and calibrated when performing
operations on multiple displays.
Individual displays can be selected by clicking on a rectangle. The currently selected display is highlighted by
a rectangle.
The layout, including the number of rows and columns in the video wall, and order of the displays is configured
by using the Layout Wizard.
NEC Display Wall Calibrator - UsEr's GUiDE | 
An individual display can be excluded from the current project by disabling it. To
disable a display, right click within the rectangle and select Disable. This feature
can be used for example if the video wall layout is not a rectangular shape.
An individual display can also be made to flash temporarily so it can be visually
identified in the video wall. This is useful to verify that a display is correctly
configured and appears at the correct location in the video wall layout. To identify
a display, right click within the rectangle and select Identify.
Additional information about a display is shown in a ToolTip by hovering the
pointer over a rectangle.