Locking and unlocking slides

Another operation that the Filmstrip allows you to do is to lock and unlock slides. When a slide is locked, all the objects of the slide, as well as the slide itself, can no longer be edited. Use the following steps to experiment with locking and unlocking slides: 

1.  Still in the Chapter04/takeTheTrain.cptx file, right-click slide 2 in the Filmstrip and select Lock Slide in the contextual menu. Take good note of the associated keyboard shortcut (command + K on the Mac or Ctrl + K on Windows).

Notice that a blue lock icon appears in the top-right corner of the locked slide thumbnail in the Filmstrip:

Now that the slide is locked, you can no longer access the slide or the objects on it.

2. Use the Filmstrip to go to slide 2 of the project.
3. If necessary, open the Properties inspector.

Notice that the options and switches of the Properties inspector are all disabled. Because the slide is locked, you can no longer...