throwable

It used to be so easy to combine PDF files in Mac OS X. You’d open the first PDF file in Preview, click the “Sidebar” button to view the page thumbnails, and drag the additional PDF files into the sidebar.

No longer. Preview in Snow Leopard uses the sidebar for both files and pages. So if you drag a PDF file into the sidebar, Preview assumes you simply want to open the file. To combine PDFs, you have to do the following:

1. Open the first PDF file in Preview.
2. Click the “Sidebar” button.
3. If the PDF file contains multiple pages and the thumbnails for the individual pages are not displayed, position your mouse over the thumbnail with the spiral-edge binding and click on the left arrow that appears. This will “open” the multi-page PDF.
4. Drag the additional PDF files onto the thumbnail for the first file.
5. Use “File->Save As…” to save the new PDF file.

Not terribly intuitive, is it? Frankly, I’m amazed this change made it past Apple’s usability experts. It clearly violates a fundamental principle of the Macintosh user interface: individual files are represented by individual windows. The previous version of Preview, which did represent files as windows and reserved the sidebar for pages within files, was much more intuitive.

Incidentally, there is a preference for choosing how Preview should behave when opening files. However, this preference does not rectify the problem of the sidebar being used for both files and pages within files. Moreover, the default value is inconsistent with the Macintosh user interface.

Further evidence of the discrepancy between the behavior of the new Preview and the Macintosh user interface is noticeable from the unusual title bar text. After opening two documents, for example, the title bar reads “document2.pdf (1 page) (2 documents, 3 total pages)”. If you make a change and then quit without saving changes, you’ll see another non-standard alert.