Drag&Drop to OSX desktop

Hi,

in a xulrunner application, we have drag&drop from distant files to the 
user file manager or application.

It works well on windows and linux (kde at least), but nothing happens 
on OSX. Is there a special flavor for it ?
We use xulrunner 15.

Here is the part of the code:

###########

event.dataTransfer.setData("text/x-moz-url", url + "\n" + filename);
event.dataTransfer.setData("text/x-moz-url-data", url);
event.dataTransfer.setData("text/uri-list", url);
event.dataTransfer.setData("text/x-moz-url-desc", filename);
event.dataTransfer.setData("application/x-moz-file-promise-url", url);
event.dataTransfer.setData("application/x-moz-file-promise-dest-filename", 
filename);
event.dataTransfer.setData("application/x-moz-file-promise", null);
event.dataTransfer.effectAllowed = "copyMove";

###########

thanks for any advice.

--
Christian