It does two jobs at once, letting you look out without stepping out and letting things in, and interpretation has fastened onto both of them.
A window performs two jobs simultaneously, and dream interpretation has fastened onto both. It allows the dreamer to see out without going out, and it allows things in. That is why the image comes down to us read as perspective on one hand and as opportunity or exposure on the other, with whatever the dreamer was doing at the glass deciding which of the two applies.
The variants are distinct enough that interpreters treat them almost as separate images.
A smashed window carries more weight than most versions of this image, generally interpreted as something forced or as a sense of protection giving way, and it is one of the few that people wake from with the feeling still attached to them. A window painted shut, or one that simply refuses to open, is read as being able to see a way through and unable to reach it. Neither is an omen. Both are descriptions of a position somebody is standing in.
Most people dreaming of a window are dreaming of one particular window. A childhood bedroom, the one above a kitchen sink, the one from a hospital corridor or a hotel during a bad week. If you recognised it, the memory attached is the interpretation, and everything general written above is at best a footnote to it.


