diff --git a/src/libmain/common-args.cc b/src/libmain/common-args.cc
index ea27aaa35..d3aac6aba 100644
--- a/src/libmain/common-args.cc
+++ b/src/libmain/common-args.cc
@@ -34,6 +34,10 @@ MixCommonArgs::MixCommonArgs(const string & programName)
                 warn(e.what());
             }
         });
+
+    std::string cat = "config";
+    settings.convertToArgs(*this, cat);
+    hiddenCategories.insert(cat);
 }
 
 }
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 060402cd0..06bb8a1c3 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -43,10 +43,6 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
             .longName("version")
             .description("show version information")
             .handler([&]() { printVersion(programName); });
-
-        std::string cat = "config";
-        settings.convertToArgs(*this, cat);
-        hiddenCategories.insert(cat);
     }
 
     void printFlags(std::ostream & out) override