After some tinkering I can at least tell you that it appears Microsoft auto groups items in the taskbar by process name. As an example I created a copy of the program Geany.exe and was able to separate them in the taskbar. This isn't an ideal solution and you can't do it with signed Microsoft binaries but at least it tells us how Microsoft is handling it. Continuing my digging it looks like all of the settings that control the taskbar are located here HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced There is an interesting key named SeparateProcess which I tried enabling without any change, so it may have another meaning.