Happy New Years to everyone......
does anybody have any answer on the question in this post?
your help is much appreciated
You can't filter on a dimension from the secondary source which isn't present in the primary.
Two possibilities (I haven't looked in detail, so I'm not sure if either of these will work for you). You might be able to make Pricing Proposals your primary data source. Or you might be able to use the "Create Primary Group" option to make the Proposal Discount Type available in the primary data source. Have a look at this knowledgebase article on creating primary groups.