Well something isn't right. it works sometimes. I'm sure my keybind is being read (using other software) every time. I'm using the neutron highway and when I have about 1 jump's worth of fuel, I will plot the next jump to the next neutron star and then "set target" to the nearest scoopable star to that target. In the past, after filling my tank at the "set target" system, I would "target next system in route" and carry on my way from neutron to neutron until I needed to refuel again. In the above case, it's still failing to work; but outside of neutron jump plots, it seems to work. more investigation is required.
edit: and yes, opening the galmap does re-target the original plot.