My action does not appear at part structure menu

Hi.

What's the difference between adding action to part structure menu and others?

I added my action to

1) <modelname="more parts actions" menufor="wt.part.WTPart">

2) <modelname="psbRelatedPartsTreeContextMenu">

in one way.

I can see my action in first menu, and i see nothing in second?

Why?

The only difference described in customization guide is

<supportedTypes>

I specified "supportedTypes" but it didn't help.

Thanks.