When I try to execute it from the budgie menu it hangs.
If I run pkexec bleachbit from the command line it works.
If I click on the bleachbit as root icon in /usr/share/applications it works.
However, if I copy the bleachbit-root.desktop file in /user/share/applications to my Desktop, mark it as executable and then click on it it hangs.
For what its worth, is works under ubuntu 18.04.