diff --git a/gui.py b/gui.py
index 495923b..6e635d0 100644
--- a/gui.py
+++ b/gui.py
@@ -1110,8 +1110,16 @@ class App:
 
     def cb_md_only(self):
         try:
-            md, path, _file_items = self._do_generate()
-            self.last_md = md
+            result_from_do_generate = self._do_generate()
+            if not isinstance(result_from_do_generate, (list, tuple)):
+                self._update_status(f"generate error: _do_generate returned a non-tuple ({type(result_from_do_generate)})")
+                return
+            num_values = len(result_from_do_generate)
+            if num_values != 4:
+                self._update_status(f"generate error: _do_generate returned {num_values} values, expected 4")
+                return
+            static_md, dynamic_md, path, _file_items = result_from_do_generate
+            self.last_md = f"{static_md}\n\n---\n\n{dynamic_md}" if static_md and dynamic_md else static_md or dynamic_md
             self.last_md_path = path
             self._update_status(f"md written: {path.name}")
         except Exception as e:
@@ -1134,8 +1142,16 @@ class App:
         if self.send_thread and self.send_thread.is_alive():
             return
         try:
-            md, path, file_items = self._do_generate()
-            self.last_md = md
+            result_from_do_generate = self._do_generate()
+            if not isinstance(result_from_do_generate, (list, tuple)):
+                self._update_status(f"generate error: _do_generate returned a non-tuple ({type(result_from_do_generate)})")
+                return
+            num_values = len(result_from_do_generate)
+            if num_values != 4:
+                self._update_status(f"generate error: _do_generate returned {num_values} values, expected 4")
+                return
+            static_md, dynamic_md, path, file_items = result_from_do_generate
+            self.last_md = static_md
             self.last_md_path = path
             self.last_file_items = file_items
         except Exception as e:
@@ -2119,4 +2135,5 @@ def main():
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
+