let NERDTreeMapOpenInTab='<ENTER>'
function! NERDTreeCustomOpenDir(node)
  call a:node.activate()
endfunction
autocmd VimEnter * call NERDTreeAddKeyMap({'key': '<ENTER>', 'scope': 'DirNode', 'callback': 'NERDTreeCustomOpenDir', 'quickhelpText': 'open dir'})