macOS Mojave -- Finder won't show favorites and can't drag new folders into favorites
Something happened to Finder on my Mac. It won't show the favorites I've selected (as per Finder->Preferences), and I am unable to drag any folder into the Favorites area.
I've included a screenshot to highlight the first problem I mentioned.
What do I need to do to regain this functionality?
If you hover your mouse over the word "Favorites", you should see "Show" button.