Click on the Selection Toolbar button to be in selection mode. Now click on the image at the location where you want the selection to start and drag the mouse to form a selection rectangle. Release the mouse when you felt you have chosen the proper region. A dashed rectangle will be drawn over the selected region. This is the active selection area also called the region of interest. It is now in selection mode. The mouse cursor changes to 'move cursor' when placed over the selection rectangle. You can now move the region by pressing the mouse over the selection rectangle and dragging the region to the desired location. When the region is dragged, it is in floating mode. In floating mode, it appears in XOR form, i.e. the colors in the selection is XORed with the colors of the image over which it is floating. To embed the selection, right click in the image outside the selection. the selection will be displayed in its original color.
This XORing of colors though may look unsual, actually improves performance while dragging the selection.
You can also copy/cut/delete the selected region . The cut/copied region can be pasted in the same image or in another image or as a new image. When pasted in the same image or anothe rimage which already has a selection region, the existing selection region will be embedded automatically before the new selected region is pasted. The pasted region is again a selection in floating mode.
When any operation is performed on the image while there is a selection present in the image, the operation is actually performed on the selection rather than on the whole image. For example : after you select a region, you choose Effects-> Adjust-> Brightness/ Contrast and then modify the brightness/ contrast and click OK, only the selected region gets modified. Similarly if you rotate,shear, resize the image when there is a selected region in it, the selected region gets rotated, sheared, resized. This provides ability to manipulate individual areas of an image selected as region of interest. Even printing of selection can be done.