From the Result tab, if a user selects a table for editing and then selects one row for deletion, the entire table will be deleted instead of the one row. This worked fine in 5.25.
To duplicate:
Enter a select statement in the Query pane that returns multiple rows in the Result tab
Select the table name from the drop down box so the table is no longer Read Only
Select one of the rows for deletion by checking its box
Click on the Delete Selected Row(s) icon
All of the rows will be deleted.