If the toolbox disappears in GIMP:
- At the top click "Windows"
- From the drop down menu select "Toolbox"
If your Tool Options disappear
- At the top click "Windows"
- From the drop down menu select "Dockable Dialogs", then "Tool Options"
- You can drag the "Tool Options" tab down to the bottom of the toolbox if you want them together.
Single Window Mode
- At the top click "Windows"
- From the drop down menu select "Single-Window Mode."