Is it possible to create your own contextmenu on an addon-button or reuse the "placesContext"

[Ruben Goethals]

If I understand my own research into this correctly, the SDK/API does not provide a way to make a.. / use the.. contextmenu on my toolbar addon button.

So, is there a way to create my own contextmenu (or should I say popup?) and set that as its context (listener)?

Another approach or solution forme:
I already succesfully did that*  (setting its context listener) to the existing contextmenu that firefox itself provides for bookmarks ("placesContext") which is about the same as I want, but how do I reuse the menuitems in there? (E.g. "Open")

*  mi.setAttribute('context',     'placesContext');  // that easy!!