diff --git a/aegisub/auto4_lua_assfile.cpp b/aegisub/auto4_lua_assfile.cpp
index 520247466..3868b58c1 100644
--- a/aegisub/auto4_lua_assfile.cpp
+++ b/aegisub/auto4_lua_assfile.cpp
@@ -888,7 +888,7 @@ namespace Automation4 {
 			description = wxString(lua_tostring(L, 1), wxConvUTF8);
 			lua_pop(L, 1);
 		}
-		AssFile::top->FlagAsModified(_T(""));
+		AssFile::top->FlagAsModified(description);
 
 		laf->ass = AssFile::top; // make sure we're still working on the most recent undo point
 		return 0;