Compact gallery display on a multi-image field displays only the first image

I have an Image field with multiple images. The field is in a fieldgroup (to allow a caption to be included under the image on the page); the display for the group is "div" and "open," while the display for the Image field is "Shadowbox," set to "gallery field" and "compact." This displays only one image on the page -- which is correct.

When you click on that image, a larger version opens in Shadowbox. This, too, is correct. However, with the settings for "gallery field" and "compact," a slideshow should be available to view all the images. This is not the case. Instead, only the first image (of the multiple images in the field) is displayed; there is no way (on the page or in Shadowbox) to display the other images.

If I set the gallery to "gallery field" and not compact, the slideshow works correctly (though multiple images are displayed on the page; this is not what I want). It's only if I set the gallery to "compact" that I have problems.