I know of something, but don't know where to get them. My son
purchased a pre-owned house that had small brackets that attached to
the window slide rails (not on the movable window). They attached
with a screw. Put above the sliding window, they limit how wide the
window would open; put below the sliding window, they limit how far
down the window would close.
Putting two (or on each side for super safety) you could limit the
window from opening and/or closing.
This should accomplish what you want. My son took them off because
he has kids as young as seven and felt it was a safety hazard
because they couldn't open a window to escape a fire. He gave me a
small bag of them, I'd guess 25 or 30.
Anyway, I have an idea you can find these at any good hardware store
or (UGH) at a big box store.
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