PrintScreen button would cause problems with third software capturing screen, even on Windows. And F12 isn't good option, as you just say, if somebody use Steam with it's overlay, then it may cause problems. We can't assume that somebody won't do that, we need to predict all possible cases and choose solution causing least problems. BTW. how is Steam Overlay with Ctrl+F12? Will it make screenshot too? Maybe it would be a solution?
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