Editing of queries disabled when more than one table

I've been doing this with no problem for years, up thru v10.2. Basically, I collect keys and then join to the table I want to edit, being careful to only select the con tents of only one table and from that select all the columns to ensure all the necessary keys are in the query window. This is a crucial function of my work, and I will have to roll back to 10.2 to be able to function, complete with the tab error messages.

I first noticed this mid 2020 but didn't report it. Today I installed 11.0 on another machine and thought it worked so I installed on my production machine.

In fact, going back to the other, it does correctly edit a different table, but when I paste in a simple test query to edit the table that needs it, the cells are locked, not allowing any changes to be made, let alone saved.

Any suggestions? Thanks.

Pic is of a query that does not allow editing.