diff --git a/doc/tagbar.txt b/doc/tagbar.txt
index 5e72622..ed5b40a 100644
--- a/doc/tagbar.txt
+++ b/doc/tagbar.txt
@@ -299,6 +299,8 @@ COMMANDS                                                     *tagbar-commands*
     Start debug mode. This will write debug messages to file [logfile] while
     using Tagbar. If no argument is given "tagbardebug.log" in the current
     directory is used. Note: an existing file will be overwritten!
+    Note also that it is usually necessary to call this command before loading
+    a file that creates problems in order to get all of the needed data.
 
 :TagbarDebugEnd                                              *:TagbarDebugEnd*
     End debug mode, debug messages will no longer be written to the logfile.