Mac: Unable to display sidebar; unable to display any notes.

[organizing 3]

Hi.  Earlier today, I was unable to display the sidebar and was unable to display any notes, other than the one that was displayed.
Exiting and restarting EN simply brought up the EN title bar and the one note that was displayed before restarting EN.
I think this problem has been happening since my upgrade to 10.x.x.  I am now running 10.18.3.
Eventually, I was able to display the sidebar by importing a document into EN.

When will this be fixed?
What is the recommended workaround?
Wouldn't a Display Home menu choice be handy to have available from the title bar menu?

Thanks.

[Boot17 1,466]

Did you happen to click the 'Expand Note' button in the top left-hand corner of the note? If you do that, the sidebar gets hidden and it persists even after closing and re-opening. I could get the sidebar to show again by creating a new note (in addition to clicking the "Collapse Note" button in the top left-hand corner).