As shown in the following example the image "Neues V12.7" was copied with "Select" and with "Select transparent region".
You can see, that the background isn't copied with "Select transparent region".
In the following example you can see how a clipping of the explorer was copied over an existing image.
(The background of the image was not deleted.)
This image was drawn up in several steps:
1. Draw up the wanted clipping in the explorer about Select -> Rectangle
2. Generate a white text above a black background about Color -> Invert
3. Mark the wanted clipping about Edit -> Select transparent region
4. Copy the clipping to the clipboard about Edit -> Copy
5. Open the wanted background-image in Hardcopy about File -> Open
6. Insert the clipping from the clipboard about Edit -> Paste into image
7. Move the clipping to the wanted position
8. Finish Select
Observe please, that this function works only, if the region which shall be copied has a one color background.