1 files changed, 2 insertions, 1 deletions

diff --git a/src/gmdocument.h b/src/gmdocument.h
index 7a0f21ee..0c6dd998 100644
--- a/src/gmdocument.h
+++ b/src/gmdocument.h
@@ -58,7 +58,8 @@ iDeclareClass(GmDocument)
 iDeclareObjectConstruction(GmDocument)
 
 enum iGmDocumentFormat {
-    gemini_GmDocumentFormat,
+    undefined_GmDocumentFormat = -1,
+    gemini_GmDocumentFormat  = 0,
     plainText_GmDocumentFormat,
 };