Favorites can't be manually rearranged in mate-menu

[ironfoot]

System: Ubuntu MATE 20.04.

Package: mate-menu 20.04.3-0ubuntu1.

Problem:
Originally reported in [https://ubuntu-mate.community/t/how-to-rearrange-favorites-in-advanced-menu-via-drag-and-drop-mate-16-10/9664/9].
Items in 'Favorites' section of mate-menu can not be manually rearranged using drag and drop approach. Editing ~/.config/mate-menu/applications.list works though.
I can confirm it works as expected in Ubuntu MATE 18.04.4 with mate-menu 18.04.3-2ubuntu1.
It may be related to a previous (now fixed) bug [https://bugs.launchpad.net/ubuntu-mate/+bug/1628188].

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Michael Parker (phatbudsj)]

+1, on mouse up I see

==> /var/log/syslog <==
Jun 1 15:01:44 pequod org.mate.panel.applet.MateMenuAppletFactory[1487]: Traceback (most recent call last):
Jun 1 15:01:44 pequod org.mate.panel.applet.MateMenuAppletFactory[1487]: File "/usr/lib/python3/dist-packages/mate_menu/plugins/applications.py", line 1371, in on_drag_data_get
Jun 1 15:01:44 pequod org.mate.panel.applet.MateMenuAppletFactory[1487]: selection.set(Gdk.SELECTION_CLIPBOARD, 8, str(widget.position))
Jun 1 15:01:44 pequod org.mate.panel.applet.MateMenuAppletFactory[1487]: TypeError: Item 0: Must be number, not str