[Feature Request] Clicking on a file should open file in last used non-PE buffer

[jimeh]

Currently with PE on the left, and two file buffers next to each other, when I select a file in PE it is always opened in the left buffer.

Instead it would be nice if the selected file opened in the last active buffer. So if the right buffer was the active buffer when I switched to PE, that's the buffer the file is then opened in.