I have a room in my house (I live in the Northeast) with two dual-pane
windows next to each other (separate individual windows within the same
frame).

Today sometime toward the end of the afternoon, one of the inner panels of
one of the windows developed a big crack. This particular room has a
problem in which, since it faces the south, the room tends to get warmer
than other rooms in the house on sunny days. This is due to heat from the
sun making its' way through the window.

I had installed tinted window film on the inside of the glass about 2 months
ago. This is the kind that adheres via static cling. The manufacturer
recommended against putting it on the inside of double-pane windows, but I
tried it anyway, since, frankly, this film wasn't even very effective, but
is CLAIMED to have a summer shading coefficient of .67 which isn't all that
great a spec to begin with. (I also figured that since the windows are 20
years old, the seal was likely shot and there would not be much risk of them
"exploding")

About 1 month ago, since the window film alone did NOT help much in keeping
the heat from getting into the room, I installed a double-cellular
honeycomb room darkening shade that has side tracks so that the sides are
virtually sealed. This did seem help a little in keeping heat from getting
into the room, but tends to trap warm air between the shade and the window.

Again, the combination of both the window film and the
shade-with-side-tracks seemed to help a little in reducing the heat, but now
today all of a sudden I have the crack in the inner pane of one of the
windows. For this reason I have removed the window film because it is a
strong suspect (simply because the manufacturer's warning "told me so"
grin).

Do you think it was the window film alone that was the cause of the cracked
glass, or could it have been due to the the cellular shade-with-side-tracks?
Do you recommend I remove the side-tracks from the shade to avoid another
crack, and just accept the fact that this room gets hotter than the others?
Could the crack have been a wild anomaly not caused by the film or the
shade?

Thanks,

J.