Is it possible to scroll to the right(i.e. horizontally) when full width of the cmdline is used?

[nyngwang]

That is:

1. I want to have a fixed-width cmdline popup.
2. I want to have the tail part of the line visible when some plugins are asking for a reply(usually with some pre-filled answer). For example, I cannot see what I typed when I was creating a folder:
   

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I know that there is already a width='auto' option for the cmdline, but I still hope it's possible to "scroll" horizontally so that I can see what I have typed. Thanks for your reading.