Hi,
Just having a play around with 19.0 studio (MSSQL backend). I started creating a new table and had to stop quickly so I clicked on the cross to close the studio. It popped up a message saying Bad or no primary index which is fair enough but when I clicked on ok it asked me if I wanted to save changes to the table. I said yes and got a whole bunch of errors following and I ended up having to task manager kill the studio session. I think it should be a bit more graceful than this and either not ask to save a table with bad or no primary index or if you say yes to still save it either actually save it or provide some graceful method of exiting without saving. I've attached the initial errors i got in order they came up. They do keep going after this though.
Cheers
Richard