You can see the pop-up menu is in the right place. Now we're making progress. My experiments have convinced me that it works like thi:. In many graphic applications the standard file open dialogs have a "Show Previews/Hide Previews" checkbox or button. The Show/Hide state selected is remembered for the next open dialog. In fact, since this is done by Quicktime, it is remembered for the next application. And the next. Its initial Show/Hide state in a newly opened application will be the same as the last one in the previous application. So, at some time I chose "Hide Previews". Later I launched Poser, and the Hide state was still in effect. Voila! I'll let the pundits argue about whether this is a Poser bug (and Quicktime feature) or a Quicktime bug.