.step function LTSPICE in multiple panes
I don't know exactly how to make it look right, but you can select a single step with an @x behind the node you are inspecting. The single line gets multiple colors, that is a bit strange, but maybe it can be fixed if you select the color yourself.

For example:



This feature is actually documented in the LTSpice Help under the Waveform Viewer -> Waveform Arithmetic topic:


  The step selection operator, '@' is useful when multiple simulation runs are available as in a .step, .temp, or .dc analysis. It selects the data from a specific run. For example, V(1)@3 would plot the data from the 3rd run no matter what steps where selected for plotting.