[feature request] Toggle Treat docking ports as stages

[Delta-38]

I often have situations where i send probes to refuel stranded ships/stages or deliver some fuel to a station and then head back to refuel somewhere else.
I would really appreciate if it was possible to toggle treating docking ports as stages as it is very difficult otherwise to judge just how much delta-v you have given/left in one or the other ship without undocking and redocking, which isn't difficult but it's a nuisance.
It is also a problem for me in the VAB as I often use docking ports instead of decouplers for said payloads and this breaks stage delta-v calculations.
(I suppose it also happens with the claw)
Thanks in advance
Paolo