BayouBlonde,

That's a different matter. I mean that pausing the game won't stop the collectible from disappearing after a while.

Ok, I tested this out. I found that if the window does not remain active, the collectible disappears. If the window remains active, the collectible remains on the screen for at least 14 minutes (that's as long as my patience lasted. hehe) At least that's the way it is working for me, on my system.