Are you left-handed? Here are the steps to set up a mouse on Windows 10.

[Windows Central]

If you use a mouse with your left hand, this guide can help you properly configure the primary button on Windows 10.
On Windows 10, when connecting a mouse to your computer, the system will usually set the left button as the primary key, as it's the default setting for any right-handed person.
However, if you're a left-handed person, or you want to switch hands after an extended period, you can use the Settings app and Control Panel to quickly change the mouse settings to reassign the left and right buttons to click, select, drag, and perform other actions using your left hand on Windows 10.

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