One of my criticisms would be-- if you can parse your sentence, as you've done, you can draw you own tree.

Another: this is not true Chomskian analysis (though maybe that's passé, Ive been out of the loop for a long time). For ex., your sent. would be something like

[S[NP it [VP was not ADJ easy]]_for to_[S[NP I [S [NP I [VP [V be ADJ alone]] [VP open NP ART N the door]]]                                                                                                                                                                                                                                                                               

I doubt that I have that right, but one problem is how to account for the _for to_ "conjunction". And also, in Chomskian analysis, adjectives that modify nouns are subordinate S's  

Also, how does this thing handle relative clauses? e.g.

This is the man who helped me
[S [NP this] [VP is [Det the N man S[NP Det the N man][Past help NP me]]]

...I think so, anyway. I could draw a tree diagram more easily than I can write it out in that format ;-(((

On Saturday, February 8, 2014 12:21 AM, Gary Shannon <[log in to unmask]> wrote:
I stumbled across this web ap that draws syntax trees from your parsed
and labeled phrase.

I tried this SOV sentence:

[SNT [NP [SNT [NP [N me][ADV alone]][VP [ND [A the][NP [J heavy][N
door]]] [V open]]] doing][VP [JP [X not][J easy]][VP [X PAST][V be]]]]

(It wasn't easy for me to open the heavy door alone.)

And the resulting syntax tree was really nice. I may use this for my
Pandári project website.