I'm pretty sure an option for this has been added in master branch.  It will eventually be released as 5.2, but there is no definite timeline yet.  You can test by using the version from master branch.  Clearly, it has not yet been released, so backup early and often, but there are some folks (myself included) who have been using it in production for several months.

Updating state to gain feedback.

What sort of feedback are you looking for?
I have not tried the Master Branch yet.
Although I am a software developer myself, I don't understand the whole git branches and structure for kmm.
I prefer to use "stable" versions.

The feedback is to confirm whether or not the developers version does what you want.
Sorry that I'm not sure if you don't understand git itself, or how the kmm team uses it.  Simplified, git is a tool to manage the source code for a program.  Every change made to the code is called a commit.  Branches are lines or threads of commits.  They are used to to track the development of different versions or feature sets.  The important bit here is that the "5.1" branch contains the 5.1.3 released version, and also some further bug fixes, but no big enhancements.  The "master" branch tracks development of new features, including a major rework of the ledger, including more control over seeing those reconciliation bars.
You can safely test a developer version by just making a copy of your .kmy file and opening that and looking at the ledger section of the configuration dialog.  Note that while there are obviously no guarantees, several folks have been using the developer version for managing our day to day finances.
Because we are working hard to make the next release, which will be called 5.2, that feature will not be backported to the 5.1 branch.  
We can close the ticket as "FIXED" in 5.2, but we'd prefer if you can confirm it does what you want, so changes can be made now, instead of waiting for a new bug to be filed against 5.2 after it is released.

Thanks for taking the time to explain about the development process.
I'll try a master branch version and give you some feedback.
Is this where to download the latest master branch, compiled for Windows?
https://cdn.kde.org/ci-builds/office/kmymoney/master/windows/

Yes, that's the right place.  If you have been using the stable version, be sure to make an extra backup before trying the development version.  Several of us are using the development version for our daily work, caution and good backups are alway a good choice.

I have downloaded and looked at the master branch. Wow, lots of changes to the ledger. The Reconciliation Display option in the Settings works fine. Nice touch to provide 3 options instead of just on/off. Separate tab for each ledger, making it easier to switch between them. Column widths are adjustable, fixing a problem I had with the date column being too narrow to display the full date. Overall, nice job.
You can mark this "bug" as being fixed in the next release.
The master branch is considered somewhat "unstable", I think.
Is there some sort of formal testing for an official release before it is declared "stable"?
A lot of it is GUI, which is hard to test automatically.
I love KMM, and it just keeps getting better.

Thanks for the feedback.  
I believe it is actually up to the distributions to formally label packages testing or stable.  While master branch can get new features before they get much testing, most of the major changes here have been there for a while.  There are certainly folks who are using this for their daily work.  
I don't know how the official roll-out will go - but we can certainly discuss whether there will be any official pre-release or release-candidate versions.
Closing as fixed in 5.2.