System windows suddenly scrolling on mouseover

[KXS11]

Dell Optiplex, Windows 11, fully up-to-date according to Dell Support Assist and Windows Update. Been using this computer for a couple of years; today, it started to exhibit a weird behavior: system windows scroll uncontrollably on mouseover. Only system windows. Using Chrome right now, no problem. PowerPoint, no problem. But if I click the time & date in the taskbar, the calendar scrolls uncontrollably. If I open Settings -> Bluetooth & Devices, the list of devices scrolls unstoppably to the bottom.I've found lots of advice talking about replacing the mouse, checking the driver, et

Continue reading...