Meaning of "label-actor" property

[Jay Strict <jay strict posteo de>]

I have two questions regarding the "label-actor" property of StWidget.

The general question is:
What is this property used for? Why do you need it and how is it
working? The documentation states "the label that identifies widget",
but that does not explain it.


The more specific question is:
In the file `gnome-shell/js/ui/popupMenu.js`, this property is set in
every MenuItem that owns a widget of type St.Label with the line

this.actor.label_actor = this.label

But not in `PopupImageMenuItem`. The label-actor property is not set
there. Is this by intention or is this a bug?


Regards
Jay