I've only been using Windows 10 for a couple of days now. If I have the Taskbar Mode set to show all windows on all taskbars, then it also shows windows that aren't actually open. Specifically, this is Store and Mail. I'm sure Windows is running these apps automatically in the background.
This isn't a big deal, but it's worth noting. Hopefully, it'll be an easy fix. If not, there are probably more important problems to fix first.
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