to put the items higher or lower in the plotting sequence.
In the Overlay Manager you can specify what should be displayed on the plot, like palettes, file name, date, time, etc.
Specify which layer to display and the display order. If e.g. an item is very low on the list (high number), it will be plotted on top of an item higher on the list, thus creating a different picture than if the two were switched around.
You specify which item goes on top, by using the arrow buttons to put the items higher or lower in the plotting sequence.
Remember to adjust the Transparency level in Grid settings.
