And on that very page they say: Drop handlers are registered under the file class's HKEY_CLASSES_ROOT\ProgID\Shellex\DropHandler subkey. Create a subkey of DropHandler named for the handler, and set the subkey's default value to the string form of the handler's CLSID GUID.
(emphasis mine)
What handles .pl files? Is it perl.dll or is it shell.dll(shell.dll being the handler for executables)? Does your system have a registered CLSID for perl56.dll?
More importantly, what happens when shell.dll gets an DDE request it may not understand or be able to handle?

In reply to Son of Windows drag and drop (boo) by boo_radley
in thread Windows drag and drop by fredt

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