Go to Languages > Application Languages > C/C++ > View
Check "Special Characters" (all sub-items are checked)
Apply (all special chars are displayed)
Uncheck any sub-item (Tabs, Spaces, whatever)
Special Characters is automatically unchecked
Apply (no special characters are displayed)
This was a problem in 17.0.3 as well.
Additionally, when I first highlighted something (Vim Visual Mode), the end-of-line special characters displayed and Special Characters was not even checked.