Below, in the black box, should be a test applet. Please drag something (preferably a file, but a browser link will also suffice) onto the "DRAG HERE" text.
When your mouse is over "DRAG HERE", the text should change to "LET GO!". This will indicate that the applet is receiving drag and drop events correctly.
When you let go of the item you dragged, the lower part of the applet should display information about each of the "flavors" of data that were in the drag. If you dragged a file, its path will appear before the flavor list. You can also drag multiple files and directories.