User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:56.0) Gecko/20100101 Firefox/56.0 SeaMonkey/2.53a1 Build ID: 20170612003001 Steps to reproduce: In latest trunks, 2.52 and 2.53, dropping a download, if setting is selected in Preferences->Browser->Downloads-> When starting a downlod: open a progress dialog, the progress dialog window doesn't appear anymore, nor other setting: When a download completes: play a sound. Actual results: To reveal the window, is it necessary select the Tool->Download Manager-Properties

The download manager has been switched to a new api in Bug 888915 because the old one was removed. The current implementation is somewhat work in progress and has several problems. Will be fixed when a dev finds the time for it.

Rocco, could you try the latest 2.53 test build from Bill: http://www.wg9s.com/comm-253/ It includes the latest download manager fixes scheduled for 2.57. If the error is not gone please let me know. Consider it a beta release. Please backup you profile if you want to go back to 2.49.x

No response. Assuming it is fixed.