Tool-bar separators and :visible etc

[Glenn Morris]

I'm trying to document the NEWS entry: "Tool-bars can display separators."

This works (after hiding and showing the tool-bar):
(define-key-after tool-bar-map [sep1] '("--")) 

so does this:
(define-key-after tool-bar-map [sep1] '(menu-item "--"))

This doesn't:
(define-key-after tool-bar-map [sep1] '(menu-item "--" nil :visible t))

although it does in a menu-bar:
(define-key-after menu-bar-help-menu [sep1] '(menu-item "--" nil :visible t))


So, it seems that tool-bar separator items do not support specifiers
like :visible, :help, etc. Is that correct?