Basics - GIMP 2.6 for Photographers: Image Editing with Open Source Software - page 37

Figure 1.16
You can set up GIMP so that all windows are open in the background window. Note that there will be only one tab for the image
window when you have set it up as the background window.
The third window is the so-called dock. To be precise, the window has
two sections. The top section has four tabs where the Layers, Channels, Paths,
and the Undo History dialog boxes can be opened. Below that you will find
the tabs for the Paintbrush, Patterns, and Gradients dialog boxes. You can
drag these with your mouse onto your desktop. As a matter of fact, you can
customize the windows to fit your needs. You can open new tab windows
from the Windows menu, drag them along to the dock and insert them as new
tabs. You may even quit the dock completely by closing it and add the tabs
you need to the Tool Options window. You may either simply drag the tabs