In the Start/Run Access>Add Program menu, selecting a file (with more than 8 characters) with the Open/Select File menu causes the file to be added twice to the list. One entry is the full file name, and the other is the 8.3-format used by DOS.
Selecting a program name from "Programs that were recently started" causes only the full file name entry.
I assume the inconsistency of the two methods indicates a bug.

Context:
Sandboxie x64 v3.50
Windows 7 Ultimate x64.

I agree it might look like a bug, but it isn't. The short name comes from the file you selected in Open/Select File. But a process that has started has just one name -- either the long name or the short name. Now it is probably possible to track the process file path in addition to the process name, and then check the if there is a corresponding short name. But I don't think I'll bother doing that. Presumably, if something appears in the process list with a particular name, then that's the name the process is going to have consistently.

tzuk, thanks for the explanation. I agree with your presumption. I consider this a resolved problem, so moderators are welcome to move this thread.