Close programs with the middle click on the taskbar instead of creating a new instance. Note that Shift+click can be used in Windows as an alternative way to create a new instance, which is not affected by this mod.
Holding Ctrl while middle clicking will end the running task. The key combination can be configured or disabled in the mod settings.
Only Windows 10 64-bit and Windows 11 are supported. For older Windows versions check out 7+ Taskbar Tweaker.
Note: To customize the old taskbar on Windows 11 (if using ExplorerPatcher or a similar tool), enable the relevant option in the mod's settings.