I read very often that people can't use copy & paste in a text mode application that makes use of
ncurses. People who use
elinks also know what I am talking about (ok, elinks doesn't use ncurses but the problem is basically the same).
All of these tools installed mouse handlers, in ncurses this is done for example via the
mousemask(3) function. Copy & paste is not done by the application but by the terminal. So if you can't copy or paste from such a text mode application that's basically because your mouse button event (that you use for pasting or copying) is not handled by the application (e.g. there is no functionality associated with it) and it also doesn't reach the terminal because of the mouse handler.
But there is a simple workaround nearly every terminal provides to directly interferact with the terminal, the
shift key (that's what lets you scroll up in a terminal using shift-pageup too)