Is it possible to open NERDTree in every tab with pressing t or T in NERDTree, if yes, How?
A better solution is to open NERDTree only if there are no command line arguments set.
" Open NERDTree in new tabs and windows if no command line args set
autocmd VimEnter * if !argc() | NERDTree | endif
autocmd BufEnter * if !argc() | NERDTreeMirror | endif
NERDTree is e.g. not helpful if you do a git commit or something similiar.