[Shotwell] Restore welcome dialog

[Arlen <arln2k sbcglobal net>]

I am setting up a computer running Linux Mint 19.1 for a newbie user. I 
would like to restore the "Welcome to Shotwell"  dialog to Shotwell 
0.28.4. I had closed the welcome window without unchecking "Don't show 
this again".

I cannot find anything in Preferences. I even tried a Timeshift restore 
to go back to a system snapshot where Shotwell had not yet been opened. 
That did not work either.

I am missing something. Google yields nothing.

Please advise as to how I can restore the "Welcome to Shotwell" dialog.

Thank you,

Arlen