Safari 11.1.1 blank Favorites window

[gogreen1]

Every now and then, bringing up Safari's favorites window on my iMac (by clicking in the address bar) produces an empty favorites window. What causes this problem and how can it be fixed?

 

[gogreen1]

Anyone? Please just jump right in!

 

[Apple_Robert]

Have you cleared Safari history or cache recently, or use some kind of Mac cleaning program? Do you have any Safari extensions installed?

 

[gogreen1]

Thanks, BasicGreatGuy. Yes, I routinely clean the history and caches, and flush the DNS cache. I have only two extensions installed--Adblock and 1Password.