How to drag-append after last page of a PDF?

Sometimes I want to combine two scanned documents (imported into DTPO via ScanSnap).

Usually I will have both documents open in separate windows. I would expect to be able to select all pages of one document in its sidebar, then drag them into the sidebar of the other document and drop them after the last existing page.

Unfortunately, while I can drop pages before any page, I can’t drop pages after the last page. The blue insertion line just won’t appear underneath the final page—it stubbornly remains stuck between the second-to-last and final pages.

Even though I’m aware of this, and there are obviously workarounds, it keeps tripping me up and interrupting my train of thought. Am I missing something, or is this a feature request?

Currently, this is not possible but we will look into it. Thanks for your patience and understanding.