diff --git a/editions/tw5.com/tiddlers/widgets/ButtonWidget.tid b/editions/tw5.com/tiddlers/widgets/ButtonWidget.tid
index a2052295e..7bdc4a7ca 100644
--- a/editions/tw5.com/tiddlers/widgets/ButtonWidget.tid
+++ b/editions/tw5.com/tiddlers/widgets/ButtonWidget.tid
@@ -44,6 +44,7 @@ The content of the `<$button>` widget is displayed within the button.
 |tag |An optional html tag to use instead of the default "button" |
 |dragTiddler |An optional tiddler title making the button draggable and identifying the payload tiddler. See DraggableWidget for details |
 |dragFilter |An optional filter making the button draggable and identifying the list of payload tiddlers. See DraggableWidget for details |
+|tabindex |Sets the `tabindex` attribute of the button to the given value |
 
 ''Note:'' In almost all other cases where a TextReference is used as a widget attribute, it will be placed between curly brackets, to [[transclude|Transclusion in WikiText]] the value currently stored there. However, when we use a TextReference as the value of a button widget's `set` attribute, we are referencing //the storage location itself//, rather than the value stored there, so we do ''not'' use curly brackets there. //Example:// we could code a button widget that sets the `caption` field of TiddlerA to be the same as that of TiddlerB as: