What is that colorful display under MechJeb's Maneuver Planner, advanced transfer to another planet option?

Question

I've been using MechJeb mod successfully for some time now. But there is one piece of its user interface that is puzzling me.

On the Maneuver Planner, when I select the advanced transfer to another planet option, I get this colorful display below, that apparently can be used to select a maneuver node. I'm saying that because the Δv and maneuver details change as I pass the mouse over the colors on that display. But I have no idea what the colors mean or how the display can be effectively used.

^{Screenshot taken when selecting a transfer maneuver from a highly elliptical orbit around Duna towards Jool.}

My questions are:

1. What is this colorful display showing?
2. What do the colors represent?
3. How can I use this display to select a particular maneuver node?

I searched but couldn't find information about it anywhere.

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^{I'm using MechJeb 2.5.8 on KSP v1.1.3.1289 (x64).}

Answer 1

Well, right on top it says "Porkchop selection", and that is what it shows, a porkchop plot.

It plots launch date vs. flight time on the axes, and the color represents the needed delta-v. Blue is lower delta-v, and red is higher delta-v.

This means that the more right you go on the plot, the later is your departure, and the higher you go the longer is the flight. Selecting blue areas means you need less delta-v.

The "Lowest dv" button automatically chooses the most delta-v efficient transfer.

You can also scroll into he plot to see some areas in greater detail using the mouse wheel.