Today, I’ve accidentally found this menu in the Slice marker’s context menu.
I do not remember that I saw such a function menu before (is it hidden new feature?? 
). Also it seems that there isn’t the description about it in Renoise Wiki yet. Though I almost understand it now, I think it’s better to describe it in Wiki since it’s a bit hard to find and understand maybe.
Anyway, I think the way to show the options is something not good. The deep Tree-menu is not fit such a nice feature. I think that it’s better to show it by a pop-up dialogue box like [Mix Paste] or [Adjust Volume].
(So, Click “Render Slices to Phrase” >> set options in the dialogue box >> OK done, for example)