[GNC] Double line mode

[Fred Tydeman]

I wanted to see what Double line mode looked like, so I enabled it via:
Edit
  Preferences
    Register Defaults
      Other Defaults
        Double line mode
I gave it a try in a few accounts; but did not like it.
I shut down Gnucash.
I restarted Gnucash.
I went back to the above Register Defaults and unchecked Double line mode.
However, some accounts still are in Double line mode.
So, it appears that preference is not global as I expected.
After reading the manual, I see the I need to disable via
View
  Double Line
for each account one by one.