I have experimented somewhat further. In a clean context as the above example standalone it seems to work fine, apart frm now needing a "width=fit" parameter.
In a more complex environment, where I not yet succeeded to pinpoint the relevant circumstances, it appears that the \type statement forces the line to extend over the full width of the line.
This follows from changing \type{} to {\tt }.
That's strange, because \type is advertised as for in-line text.
I hesistate however to make this change, because I hav used \setuptype to get uniform behaviour over the whole document.
Is there someone who has an idea what might causing the difference?