Tried this on a bunch of PDFs but can't seem to duplicate the bug. I wonder if it might be an artifact of some earlier version of PDF. The version shows when you Get Info on the file in Preview. Might be worth checking out.
The resolution to the apparent problem combining PDFs is simple, as stated above - you now have to drag the source PDF ONTO the target PDF. Before you would just drag the source PDF anywhere onto the Sidebar.
Why? Preview now displays multiple PDFs differently. Previously, selecting more than one PDF in the Finder would open them in separate Preview windows. Now only one Preview window opens, and the PDFs are shown sequentially in the Sidebar. So the metaphor of the Sidebar being your entire single PDF has changed, which is why you need to be more specific in what you drag where.
If you try this, you'll see that there's feedback onscreen: an orange rectangle outlines a multi-page PDF, and orange lines show you where you're inserting your source document or pages.
I find this better, since I am on a daily basis combining PDF files, and prefer that all the PDFs I open show up in one window rather than multiple windows across my screen. The only improvement I'd suggest is a horizontal break between each separate or group of PDFs so that a user doesn't get the impression that they are combined simply because they are living together in the Sidebar.
Comments
Ouch. Does this happen every time?
About 50% of the time.
Why? Preview now displays multiple PDFs differently. Previously, selecting more than one PDF in the Finder would open them in separate Preview windows. Now only one Preview window opens, and the PDFs are shown sequentially in the Sidebar. So the metaphor of the Sidebar being your entire single PDF has changed, which is why you need to be more specific in what you drag where.
If you try this, you'll see that there's feedback onscreen: an orange rectangle outlines a multi-page PDF, and orange lines show you where you're inserting your source document or pages.
I find this better, since I am on a daily basis combining PDF files, and prefer that all the PDFs I open show up in one window rather than multiple windows across my screen. The only improvement I'd suggest is a horizontal break between each separate or group of PDFs so that a user doesn't get the impression that they are combined simply because they are living together in the Sidebar.