1. Click on the "zoom rectangle" tool (circled in red in the first frame at left).
2. Draw a rectangle around the region you want to highlight. When you release, the energy plot will be redrawn with an expanded view of the region you chose.
3. You can repeat and expand as often as you like.
4. When the energy axis is greatly expanded, the labels on that axis will show the last few significant digits of the energy, to which you must add the offset (circled in red in the last frame at the right). In the plot at the right, the offset is 4.182e1 = 41.82. We have labeled the energy divisions in that plot; the zoom tool does not do that.
Zooming into the Energy Plot