scrooloose/nerdtree — pull request #356 by alvan (2014-07-09 07:21:22+00:00)
Title: Use event BufLeave instead of BufWinLeave to record screen state

Use event BufLeave instead of BufWinLeave to record screen state to avoid undefined b:NERDTree error .
The BufWinLeave event also triggered when exiting(:qa), will cause an undefined b:NERDTree error.