RESOLUTION #1:
Use the data grid in the Schema Browser to make changes to the data.
RESOLUTION #2:
When clicking the button to disable read-only, the Define Custom Statements to Edit window appears. By default all of the selected columns are included in the UpdatableColumns selections.
If every field included there is updated, it saves the changes. If only some of the fields are updated, then the changes don’t save.
So, remove all the columns from that list that will not be updated.