It's very nice to see that the user can now arrange taskbar buttons by dragging them around. I REALLY hope that the same will be true for the popup preview windows that display the application's various windows. This is because it allows the user to arrange
the internal order of windows inside the popup thereby saving time when using the same windows to type different things in.
You may have different powershell instances launched but the first one is pointed at c: and the second one is pointed at c:\program files\. If you, the third one pointed at something else. By allowing the user to control the order of the 'preview' windows inside
the popup, you save time when trying to do repetitive tasks that require frequent window switching... User in control!
"Problems and issues" is putting it entirely in a different class of difficulty. The reality is: It is simply impossible to detect arbitrary mutable shared state without changes to the LANGUAGE and the RUNTIME.
That is several orders of magnitude more complex than implementing a library. In fact, don't bet that it will ever be done for you. Just like all those 'new programming features' talked about in the mainstream press that will automate your job for you.