Drag and Drop in Tkx

Here's a new thread with a suggestion to include the results in the Tkx
documentation (following an earlier thread on documentation issues).
How do we do drag and drop in Tkx? Does anyone have a simple script that
demonstrates this for, say, a listbox widget that allows dropping in file
names from folders on the desktop (in Windows, Mac, and Linux)? Or, a text
widget that allows dropping in the contents of files from a simple text
file.

Even in Tcl, this seems to be a poorly documented issue.
Laurence.