In Comment tool, Rectangles now draw invisible -- they are there, but cannot be seen

In Acrobat Pro DC (version 2015.017.20053), in the Comment tools, I changed the border color and fill of a Rectangle.  It then became invisible!  And any new rectangles are also invisible.

In properties, I can change the border color and the fill color, but it still doesn't show! I can select it and set a pop-up note, and move it around; it shows up in the comments list.  But I cannot see it.  I keep wanting to "bring it forward."

I really need to use the Rectangle in my mark-ups.  Does anyone have any advice?

I'm using a mac.