UB 20.04 Software center no longer displays Categories at the bottom. I just noticed this today. I signed uo for Ubuntu Pro a few days ago and noticed it added alot of lines to the sources list.
This software glitch was NOT caused by subscribing to Ubuntu Pro. My other laptop did not do this. I tried to build an ISO of the system with PinguyOS Builder and it failed and took out All of apt/sources and who knows what else. Synaptic works fine abd does the job.