...because not every picture has to be picture perfect
You are right, of course, and I agree that sometimes a deliberate abnormality in general
composition of a piece of art can have a lifting effect on the overall presentation. But in
this scenario I do not agree, I'd find the image much more satisfactory if the window
could have been mistaken for a wall-painting at first glance, I think it would enhance the
terrain overall. But, then, it is a small detail. I will not continually chastise you to
change it if you do not want to.
But if you are going to keep it half-hidden, might I suggest you use subtle glow doodads,
maybe even flares, to slightly enhance the transfixing effect of the moon?
Come to think of it, I think you would also get a better indoors impression if you used the
black glow doodad to slightly frame the edges of the terrain, to indicate that the room is a
little darker where the window isn't at.