This operator is easy. From the source, get the (x, y) coordinate of a pixel and assign it to the corresponding (x, y) coordinate on the target document. This can be done as follows:

System::Void btnCopy_Click(System::Object^  sender, System::EventArgs^  e)
{
    Graphics ^ graph = pbxSource->CreateGraphics();
    Bitmap ^ bmpSource = reinterpret_cast<Bitmap ^>(pbxSource->Image);
    Bitmap ^ bmpDestination =
                gcnew Bitmap(pbxTarget->ClientSize.Width,
                             pbxTarget->ClientSize.Height);

    int width = bmpSource->Width;
    int height = bmpSource->Height;

    for(int x = 0; x < width; x++)
    {
        for(int y = 0; y < height; y++)
        {
            Color clr = bmpSource->GetPixel(x, y);
            bmpDestination->SetPixel(x, y, clr);
        }
    }

    pbxTarget->Image = bmpDestination;
}

This would produce: