Operations such as File > Open now, by default, use the directory of the file most recently edited in the IDE as the default directory in the file dialog.
This behavior is controlled by the new preference option Preferences... > Environment > General > Use recent directory for opening files .
If this option is deselected, the current working directory will be used, which is the behavior seen in LispWorks 5.1 and previous versions.
Note that this does not apply to the Editor tool itself, for which the file dialog always uses the directory of the currently visible file as the default directory.