diff --git a/src/visualinfo.c b/src/visualinfo.c
index 3e9b93b..3ef611e 100644
--- a/src/visualinfo.c
+++ b/src/visualinfo.c
@@ -663,6 +663,8 @@ VisualInfo (GLContext* ctx)
           fprintf(file, "gs ");
         else if (GLX_STATIC_GRAY == value)
           fprintf(file, "sg ");
+        else if (GLX_X_VISUAL_TYPE == value)
+          fprintf(file, " . ");
         else
           fprintf(file, " ? ");
       }