Docking tool options back onto the toolbox in GIMP?

I just recently downloaded GIMP 2.6 I believe it is. And somehow I accidently undocked my tools options from my toolbox. I have my tools options up in a seperate tab, but I can't seem to figure out how to dock it back onto my Toolbox. Please help me. I looked at the GIMP manual and it doesn't tell me how to dock it back on, only that it's important to keep it docked on the toolbox.