You can use the mouse wheel to scroll, and you can also use it as a button. Pressing the wheel switches to other open apps or windows on your desktop. Sometimes while scrolling, you might accidentally press the wheel and unintentionally switch to another open app or window. That's why the active window seems to disappear, but it's actually still open on your desktop. If you want to return to the previous window, press the wheel until that window appears again, or use the Windows taskbar to switch to the window that you want.
To fix the problem, try to avoid pressing down on the wheel while scrolling.
You can also turn off the wheel button if you want to use the wheel only for scrolling. To do this and to follow the additional troubleshooting steps listed below, first visit the Microsoft Mouse and Keyboard Center download page, select the version you want to use, and follow the instructions to download and install it.
To disable the wheel button
Start Microsoft Mouse and Keyboard Center, and select Wheel.
Select Disable this button.