I follow this and this to change the default application. But it does not work.
I try to change to Text Editor as default application to open xml file but it does not change. By default it is firefox.
cat /etc/os-release NAME="Ubuntu" VERSION="18.04 LTS (Bionic Beaver)" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu Bionic Beaver (development branch)" VERSION_ID="18.04" HOME_URL="https://www.ubuntu.com/" SUPPORT_URL="https://help.ubuntu.com/" BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/" PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy" VERSION_CODENAME=bionic UBUNTU_CODENAME=bionic