bug#12750: Highlighting text no longer works

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 28 Oct 2012 09:16:13 -0700
> From: Bruce Korb <bruce.korb@gmail.com>
> 
> For many years, I have selected text and then pasted it where I wanted.
> There is a new feature in emacs:  selected text is no longer in the
> pasteable buffer.  I must move my hand from the mouse to the keyboard
> to copy the text and then back to the mouse to paste it.  This is a bug.

Actually, it's a feature: it was deemed a Good Thing to behave like
the other GUI applications.

> Pending a fix in the next emacs release, how do I work around this problem?

See this entry in NEWS (what you want, if you still do, is at the
end):

  ** Selection changes.

  The default handling of clipboard and primary selections has been
  changed to conform with modern X applications.  In short, most
  commands for killing and yanking text now use the clipboard, while
  mouse commands use the primary selection.

  In the following, we provide a list of these changes, followed by a
  list of steps to get the old behavior back if you prefer that.

  *** `select-active-regions' now defaults to t.
  Merely selecting text (e.g. with drag-mouse-1) no longer puts it in
  the kill ring.  The selected text is put in the primary selection, if
  the system possesses a separate primary selection facility (e.g. X).

  **** `select-active-regions' also accepts a new value, `only'.
  This means to only set the primary selection for temporarily active
  regions (usually made by mouse-dragging or shift-selection);
  "ordinary" active regions, such as those made with C-SPC followed by
  point motion, do not alter the primary selection.

  **** `mouse-drag-copy-region' now defaults to nil.

  *** mouse-2 is now bound to `mouse-yank-primary'.
  This pastes from the primary selection, ignoring the kill-ring.
  Previously, mouse-2 was bound to `mouse-yank-at-click'.

  *** `x-select-enable-clipboard' now defaults to t on all platforms.

  *** `x-select-enable-primary' now defaults to nil.
  Thus, commands that kill text or copy it to the kill-ring (such as
  M-w, C-w, and C-k) also use the clipboard---not the primary selection.

  **** The "Copy", "Cut", and "Paste" items in the "Edit" menu are now
  exactly equivalent to M-w, C-w, and C-y respectively.

  **** Note that on MS-Windows, `x-select-enable-clipboard' was already
  non-nil by default, as Windows does not support the primary selection
  between applications.

  *** To return to the previous behavior, do the following:

  **** Change `select-active-regions' to nil.
  **** Change `mouse-drag-copy-region' to t.
  **** Change `x-select-enable-primary' to t (on X only).
  **** Change `x-select-enable-clipboard' to nil.
  **** Bind `mouse-yank-at-click' to mouse-2.