Drag and dropping 1 page PDF into another 1 page PDF does not work

Issue:

Drag and dropping 1 page PDF into another 1 page PDF does not work

Answer:

This is as designed. 

When Page View is open you move your mouse cursor over the page number then click and drag into the desired pdf that is open.

Dragging the page when it's highlighted in red does not copy it into the desired pdf.