I have a combined document, it is a text document imported as pages and a PDF document imported as an electronic document sharing the same entry ID.
In the thick client you can right click and open pages to view the text document or right click and open electronic document to open the PDF document.
In the Web Client I can only open the PDF. It doesn't matter if you right click and choose to open Pages, it just opens the PDF anyways, which is bound to the electronic side of the entry.
Furthermore, there is no way to delete the Pages side of the entry without deleting the electronic side. The only option is to delete the electronic, then the option to open pages becomes available and you can delete the pages (or just delete the entire document).