When you select a region on a graph in Logger Pro 3 or Graphical Analysis 3, the region is shown as an intersection of light gray bands, darker gray in the central region.

You cannot change the selection color in Windows. The gray color is light to keep points inside the region visible.

If your computer monitor contrast is set to too high a value, this selection is hard to see. Reduce the contrast setting, and you’ll be able to see the selection region clearly.

The Macintosh version changes colors as per the OS setting for Highlight Color.