Gregory's Server
Oh, sorry about that. Everything you've mentioned should be pretty much like that.
Though PDFs either have a background shape or don't. It only makes sense to select one on opening for raster images, rather than vector images.
What was the version you were last using?
@doctormo I used a reasonably new version, about a few months ago. Don't know the details anymore, but I remember getting the multi-page canvas after importing a PDF, then a dropped PNG got lost under hundreds of vector layers in one of the pages, and I believe adding a white layer to the transparent background also failed because of the layer mess.
Maybe auto-grouping of the vector layers of each imported page would help.