I made some debugging about this issue. It is due to the action names in the .desktop file not corresponding to the DBus actions of totem, plus the mute action isn't among the one implemented in totem.
I made a patch to fix the names and add the mute action to totem. This is my first contribution to Ubuntu so please tell me if there's something wrong. Tested under Ubuntu 18.04 and 18.10 ** Patch added: "1-3.26.0-0ubuntu6.2.debdiff" https://bugs.launchpad.net/ubuntu/+source/totem/+bug/1726688/+attachment/5228010/+files/1-3.26.0-0ubuntu6.2.debdiff -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1726688 Title: totem media player in the Ubuntu dock right click menu does not work, rewind does not work, nor full screen works To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/totem/+bug/1726688/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs