You can have 2 additional internal clipboards

if you add this to macros.cfg :

copy_to_clipboard1 {
  $tmp = getclipboard();
  id(ID_EDIT_COPY?);
  $clip1 = getclipboard();
  setclipboard($tmp);
}

copy_to_clipboard2 {
  $tmp = getclipboard();
  id(ID_EDIT_COPY?);
  $clip2 = getclipboard();
  setclipboard($tmp);
}

paste_from_clipboard1 {
  $tmp = getclipboard();
  setclipboard($clip1);
  id(ID_EDIT_PASTE?);
  setclipboard($tmp);
}

paste_from_clipboard2 {
  $tmp = getclipboard();
  setclipboard($clip2);
  id(ID_EDIT_PASTE?);
  setclipboard($tmp);
}

and this in the menus.cfg: to the TextPopup - Function

-
  macros(copy_to_clipboard1, Copy to internal Clipboard 1)
  macros(copy_to_clipboard2, Copy to internal Clipboard 2)
  -
  macros(paste_from_clipboard1, Paste from internal Clipboard 1)
  macros(paste_from_clipboard2, Paste from internal Clipboard 2)

so that it looks like this:

TextPopup {
        &Undo = ID_EDIT_UNDO?
        -
        Cu&t = ID_EDIT_CUT?
        &Copy = ID_EDIT_COPY?
        &Paste = ID_EDIT_PASTE?
        &Delete = ID_EDIT_CLEAR?
        -
        Select &All = ID_EDIT_SELECT_ALL?
  -
  macros(copy_to_clipboard1, Copy to internal Clipboard 1)
  macros(copy_to_clipboard2, Copy to internal Clipboard 2)
  -
  macros(paste_from_clipboard1, Paste from internal Clipboard 1)
  macros(paste_from_clipboard2, Paste from internal Clipboard 2)
        bmpmenu()
}