Hello!
I've been having this issue for quite a while on my Debian stable, with mate-hud version 22.10.3-2. Furthermore, downgrading the mate-hud didn't solve the issue.
To have the problem, open Chromium web browser (including Chrome, Brave, Edge, Chromium web apps, and their Flatpak/Snap/AppImage variations), and press the HUD activation button. Then, the keyboard completely freezes and the mouse cursor moves but doesn't click. The only solution is to switch to another TTY and restart the system.
Other apps work perfect with the HUD. It only happens on Chromium web browsers.
After looking for an error in the dmesg, journalctl, and x logs, I found the error.
Here what mate-hud python script gives when you try to activate [or accidentally press :(( ] the HUD:
Traceback (most recent call last):
File "/usr/lib/mate-hud/mate-hud, line 870, in hud
appmenu_success = try_appmenu_interface(int(window_id, 16))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/mate-hud/mate-hud", line 616, in try_appmenu_interface
expanse_all_menu_with_dbus(dbusmenu_root_item[1], True, "")
File "/usr/lib/mate-hud/mate-hud", line 592, in expanse_all_menu_with_dbus
dbusmenu_object_iface.AboutToShow(item_id)
File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 141, in __call__
return self._connection.call_blocking(self._named_service,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/dbus/connection.py", line 634, in call_blocking
reply_message = self.send_message_with_reply_and_block(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Failed: error occurred in AboutToShow
*edit: corrected typos