The Essence of Software: Why Concepts Matter for Great Design

by Daniel Jackson

That example illustrates a problematic interaction when the user makes a mistake (albeit one that is very easy to make). My second example arises in the context of a task that I often want to perform, and for which, due to this design, I needed to invent a workaround. In Lightroom, you can attach keywords to your images. I do this to identify people in pictures. A common task I want to perform is to check a particular keyword, or perhaps replace it by another one. So let’s suppose I key-worded images of my daughter with the keyword “Rebecca” but I want to replace it by the keyword “Becca.” So I filter for images carrying the first (old) keyword; to these, I then add the second (new) keyword in bulk. So far so good. Then I remove the old keyword, and all the images disappear, because they no longer carry the keyword of the filter. This is a serious problem, because I want to complete the task by saving the keyword edits in all these photos to their files on disk. Now, without the photos selected, I cannot execute the save command. (The workaround, incidentally, is to first filter the photos on the required keyword; then to select all; then to turn off the filter, revealing a larger collection in which the relevant photos are still selected. Now they can be edited in bulk without any disappearing as their keywords are changed.) Following Apple’s design of marking the items in the original filtering with their properties would not work here, since the filtering is more sophis...