That's a common misconception. Microsoft paid Apple so they would drop a lawsuit that accused Microsoft of stealing concepts and ideas from Apple's MacOS and putting them into Windows. Which was ironic because Apple had stolen them from the Xerox Palo Alto research lab previously. Gates anecdotally told Jobs "Steve, it's like I broke into a house to rob it and found out you'd already cleaned out the place".

But it was Apple not Xerox or Microsoft that had put those concepts on the market first and they would've had a strong case. So Gates paid for it to go away and also arranged some cross licensing so it wouldn't happen again.