OK, I hear you and will be careful. But your suggestion, to unlink
thoughts manually one at a time, is not really helpful if you have hundreds of thoughts. Still, I would say that the current design runs contrary to the principles of a good GUI design, where the display gives you immediate feedback about what's affected by your actions. After Ctrl-Clicking the child I saw the marked thoughts. My first impulse was: Fine, now I can unlink the marked items. Only then did I wonder why there were so many thoughts in the selection box. That's an invitation for mistakes. Reminds me of some computer games: Click a button (gate), and them some hidden door (invisible thoughts) opens (are marked). If you Ctrl-Click a gate when the selection box is already filled with thoughts you have a hard time to keep everything under control.
Reinhard, TB 10.0.53.0, WIN 10
Quality is the result of attention paid to details.