Hmmm... I am invoking the process through a REST interface. I guess there is no way to set the HTTP header just straight from within Workbench for that REST service?

Hmm.. I have the impression I need to do something more thank just that. Indeed I got the popup to work by changing the MIME type, but that also removed the .pdf extension for some reason. I'f I keep using PDF the browser just always opens it, whilst that same browser on many other sites forces the ...

Is there a way to force a PDF rendered by LC to be downloaded by the HTML client, instead of opened in the browser? When I use the REST url the browser tries to open the PDF and I don't get the download option.