I have noticed that with very large tables in PostgreSQL 11, studio 9.1.4 takes either a VERY long time to show tables in the schema editor or it does not open them at all and I have to crash studio to recover (Windows). I am talking about tables with 40 million+ rows. Looking at the network interface I do not see much activity so I am not sure what studio does in the background. pgAdmin is fine. No issues there.
Please, address it as soon as you can.