This dialog allows the user to make a normal texture into a seamless texture by blending the edges. The left hand panel shows the original texture. You may select sub regions of this by clicking and dragging the mouse over this image. This defines a crop area; this becomes area to be used to make the seamless image. You may clear this crop by pressing the Clear Crop button.
The right hand panel shows a preview of the seamless bitmap. To see the preview tiled in a window, press the Test button and this will give you a good visualisation how well the seamlessness works for the texture.
The overlap slider determines how much to overlap and blend the edges of the source image.
You may save the seamless texture back to disk using the export button.