Today a person mentioned to me Hugh G. Well's short-story "The Door in the Wall," and, like the green door it describes. I was revisited by my first experience of reading it as a young girl*. I never returned to it until today, thanks to internet resources.
 
It seems that Nabokov, who used to like Wells in his early childhood, might have equally been haunted by a green door.His way of expressing this opening into "arcadia," as a parallel world co-existing with ours, changed along the years, but... the longing remained.
We find its progression in, for example, "The Woodsprite," "Sounds," "Gods," "La Veneziana," "A Visit to the Museum." It is present in "Glory," in "Speak,Memory." It is found in "Lolita" (perhaps this green door serves as the deep link with the German Ur-Lolita?) and in "Ada."
 
Nevertheless, although this "green door" suggests the familiar indication of  a "hereafter" or "other worlds," I surmise it indicates still another dimension of ecstatic experience, it is something that applies to the present moment, something that remains permanently accessible, always within reach through time (not space), through words...    
 
...............................................................
* Excerpts from H.G.Well's short-story:
"It was wonderful to me, because the pages of that book were not pictures, you understand, but realities." ...They were realities--yes, they must have been; people moved and things came and went in them; my dear mother, whom I had near forgotten; then my father, stern and upright, the servants, the nursery, all the familiar things of home...  so at last I came to myself hovering and hesitating outside the green door in the long white wall, and felt again the conflict and the fear."
[...]
"There are times when I believe that Wallace was no more than the victim of the coincidence between a rare but not unprecedented type of hallucination and a careless trap, but that indeed is not my profoundest belief...I am more than half convinced that he had in truth, an abnormal gift, and a sense, something--I know not what--that in the guise of wall and door offered him an outlet, a secret and peculiar passage of escape into another and altogether more beautiful world. At any rate, you will say, it betrayed him in the end. But did it betray him? There you touch the inmost mystery of these dreamers, these men of vision and the imagination We see our world fair and common, the hoarding and the pit. By our daylight standard he walked out of security into darkness, danger and death. But did he see like that? " (if you haven't read the story, it's here <http://www.pagebypagebooks.com/H_G_Herbert_George_Wells/The_Door_in_the_Wall_And_Other_Stories/The_Door_in_the_Wall_Chapter_I_p1.html> .)  
 

All private editorial communications, without exception, are read by both co-editors.