Getting the Tool options back, once for all

[Ofnuts]

Now, the Tool options dialog is known to detach somewhat spontaneously, so to avoid further mishaps you can lock it down by:

1. Making sure it is the displayed tab
   
2. Clicking again on the |<| icon,
   
3. Clicking the Lock tab to dock entry:
   

   

You can also set up Gimp to ensure  that accidental UI changes are not kept between sessions (so you recover your initial layout by restarting Gimp). See this other tutorial for details.