The scrollbar for the Raw Power edit adjustments is visible only while scrolling. It does not respond to the scrollbar setting in the General pane of the System Preferences (MacOS 11.2.3). The Keep Only One Adjustment Open setting is a good substitute, but …
Yes, you are correct. There is a spacing issue that resulted in this limitation – to fix it I would need to re layout the whole panel. What kind of mouse are you using?