Comment 7 for bug 1827302

Sorry my bad, the diff is reversed. Use the following commands instead:

    mkdir tmp
    cd tmp
    sudo apt install devscripts build-essential fakeroot dpkg-dev
    sudo apt-get build-dep xfwm4
    apt-get source xfwm4
    cd xfwm4-4.12.5
    patch -R -p1 -i xfwm4_slack_fix.diff # !!! Point it where the patch is located!!!
    debuild -b -uc -us
    sudo dpkg -i ../xfwm4_4.12.5-1ubuntu0.18.04.1_amd64.deb