Nice plugin, this is invaluable since my python projects were starting to get a bit unmanageable with NP++! Now navigation is a breeze again :)
There's just one thing that doesn't work that well. For instance, class constructors in python are all named __init__. Since SC shows only the method name, they can't be distinguished -- unless I hover them with the mouse. Same for all common method names. Since you already show the complete name on mouse hover, could you make it an option to show it in the list too?
Alternatively, you could collapse the classes and methods nodes into one (classes), show classes as child nodes, and respective methods as their child nodes. This is more complicated though, and if you stick with the previous method I'll be happy anyway!