The solution I found that worked for me was, right click got to view drop down to hide side bar and click the box were back
absolutely. true, why would they hide the plus (+) absolutely terrible User interface design. Apple is really dumb sometimes. I've been using Mac OS since 1986 Mac 512K. The best OS design was under Jean-Louis Gassée.Thank you! That is just bad by design if you all have this issue. I would be ashamed as a developer that all my users have this issue already for such long time. But anyway, thanks!
Thank you!Next to the "Favorites" header in the sidebar tap the + button. You'll see it as an option in the drop-down menu.