Sticky Keys is an operating system feature designed to minimize the repeated pressing of keys. People typically trigger this behavior by accident when they quickly press a key many times consecutively. Gamers in particular can frequently get tripped up by Sticky Keys, since they have a habit of rapid-fire button tapping.
Press both SHIFT keys at the same time. This reset everything to normal. That is all.
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If you find the Sticky Keys feature particularly annoying, it can be turned off for good.
You have now prevented Sticky Keys from re-activating in the future.
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