New->Fortran Files does not have an option for
creating a Fortran file
with a .F90 or .F95 extension.  It is possible to
create a file with a
.f90 extension, however the capital F tells the
compiler something
about the contents of the file that the lower case
f does not.  The
compiler will run the preprocessor over a file
with a capital F in the
name by default, but it will not default to doing
that for files with
lower-case-f extensions.  That means that not
recognizing that file
type can cause some files not to compile.