Basics - GIMP 2.6 for Photographers: Image Editing with Open Source Software - page 38

you need from the dock, before closing it, or you click on the tiny little arrow
symbol on the right of the Tool Options window and choose the desired tabs
from Add Tab . And if your GIMP starts looking too weird, you can always reset
everything to default by opening Edit > Preferences: Window Management and
clicking Reset Saved Window Positions to Default Values . Then just restart your
GIMP and it's as fresh as on the first day.
Figure 1.17
The submenu Add Tab, opened from the Tool
Options window