This area shows GIMP's basic palette, consisting of two colors,
the Foreground and Background, used for painting, filling, and
many other operations. Clicking on either of the color displays
brings up a Color Editor dialog, which permits you to change it.
Clicking on this small symbol resets the Foreground and Background
colors to black and white, respectively.
Swap FG/BG colors
Clicking on the small curved line with two arrowheads causes
the Foreground and Background colors to be swapped. Pressing the
x key has the same effect.