The title to my question may seem a bit odd as I can't figure out how to write it.
Heres the problem. I know that I can add to or subtract from a selection by holding the Alt key or the Ctrl key down while I draw the second selection. However, I can't always position that selection at the right place when I draw it and when I let the mouse button up, Wham its done and I can't reposition it later. Is there a way to do this? that is, make to selections then move them together and make the cut or additions. Any links to tutorials on the subject would also be appreciated.