Ok, it's not a bug. Just in your connection type another database. Now you can delete the previous default database.

I just had this problem with DBeaver 7.1.0.

1. Open your CLI terminal ;)

2. Type mysql -u root -p (or whatever your SQL server is, Postgres, etc)

-u root is for user root

-p is for password--it will let you type it in after you hit enter

3. Type USE databasename (where databasename is the name of your DB in DBeaver)

4. Type SHOW tables; (this will list all the tables in that DB)

5. Type DROP TABLE tablename; (where tablename is each table)

I searched for a while in DBeaver, but the easiest way is to simply use the MySQL command line interface and input a couple commands.