diff --git a/docs/dev/Lua API.rst b/docs/dev/Lua API.rst
index 5a1b562ee..c63be53f4 100644
--- a/docs/dev/Lua API.rst	
+++ b/docs/dev/Lua API.rst	
@@ -4816,6 +4816,7 @@ cycle through by pressing a specified hotkey or clicking on the text.
 It has the following attributes:
 
 :key: The hotkey keycode to display, e.g. ``'CUSTOM_A'``.
+:key_back: Similar to `key`, but will cycle backwards (optional)
 :label: The string (or a function that returns a string) to display after the
     hotkey.
 :label_width: The number of spaces to allocate to the ``label`` (for use in