[UPDATED] There was an older Idea post — which had more than 100 votes but is now archived and not visible except to moderators — which asked for the option to control account order/grouping/sorting in the sidebar. The developers originally marked as "Under Consideration" with a note that "the team is working on possible custom grouping in the future." This was then changed to "Planned", and then changed again to "Not Planned" due to unexplained complexities. This Idea thread is essentially a resurrection of the request to allow users to control the order of accounts in the sidebar.
This Idea has not been nixed as "Not Planned", but the most recent note from the developers above states that they are only considering a limited sidebar customization option to allow reordering within each sub-group, but not custom account groups. (Users can currently achieve reordering within sub-groups by simply adding numerical prefixes to account names, so implementing such a limited change would be positive, but fall short of what many users have previously asked for.)
Nonetheless, since the future is uncertain, I think anyone who wants flexibility/control over how accounts are grouped in the sidebar should vote for this Idea post. And then add any comments you have about how you would like to see this implemented. (But add your vote above first!) Even Ideas marked as not planned can possibly be resurrected in the future base don customer demand and/or changes in the underlying technology.
Manual re-ordering within account categories is allowed in the Quicken for Windows product. It is quite useful in my experience. I don’t understand why the Mac product wouldn’t offer it too.
there are work arounds to make this work but I think this thread is really wanting to be able to control the category that accounts are listed in. And, also allow new customizable categories.