GNAT GPL 2017 X86-64 GNU Linux (64 bits)

[lyttlec <lyttlec@removegmail.com>]

I installed the above on both a new Ubuntu and Redhat release. Building
from the command line and EMACS Ada mode all work. But try as I might, I
cannot get GPS to work properly. Every project loaded, including the
tutorial, shows a "?" icon before all source files rather than the
triangle. This is even with default VCS set to "None" and no VCS in the
project file. I've also tried opening, editing, and saving the files to
no effect.
Is there some trick to installing GPS?
GPS would be very helpful on my project if it would work the way the
tutorial indicates.