skip NERDTree window

[searene]

First, a big thanks to this awesome plugin, I use it a lot and it works just great.

When I press 'e' on the quickfix window, ag will close it and jump to the first window of vim. For me, it's usually NERDTree, and I have to press C-w-w to switch to my main window.

So is there a way to specify a list of windows that I want to skip when pressing 'e'? So I don't have to switch to my main window everytime. Or even better if you can find the real window that consists the string that I want, instead of just jumping to the first window.