Yea, GIMP is not really user friendly but it didnt take me long to understand, and  thanks to it i have less problems understanding Photoshop (which i found a little harder as i was used to GIMP)

I see you got your brushes and layers dialogs (word? my GIMP is in Spanish) back. To get them in one single window again its just a matter of holding and dragging windows into others: once you have both layers and brushes windows up (when you install GIMP, the Channels window also comes in the window you mention but i rarely used it)  click on the name of any of them and drag it to the other window.

You must click on the window's name that shows up below the tab (for example, in the layers window hold down where it says "Layers" in small letters above the layer mode selection part). Once you drag it to the other window, both will merge into one.

Its a bit confusing, though. If you want both the layers and brushes to show up at the same time (like when GIMP is just installed) then you must drag the window to some tiny bars that are at the top and bottom of the window. If you drag it somewhere else then the windows will join in one, but you will have to click tabs to switch between  layers and brushes.


...GIMP not being user friendly makes it even harder to explain, even I am confused with what i just typed :/ I hope i didnt confuse you alot, i guess images would help to make this clearer (unfortunately, im not home right now so this computer doesnt have GIMP to get some shots :/ )