Help with renumbering pages

If I am working on an original pdf document and wish to prune the document and delete some pages to create a smaller document I rename and save, I am used to doing this with the original doc on screen with thumb nail pages on the left pane.

I used to select the page or sequence of pages to delete  for example page 3-7 and  the document would automatically renumber page 8 as the new page 3 etc etc throughout the pruning task.

Today this is not happening and I have not changed any settings.

How can I restore this helpful feature?