master 0ba43e15d9: Note caveats of `follow-tooltip' with system tooltips

[Po Lu]

branch: master
commit 0ba43e15d9c9ffb3df8aeb3a7e446d9a4d62ccff
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Note caveats of `follow-tooltip' with system tooltips
    
    * lisp/mouse.el (mouse-drag-and-drop-region): Turn off system
    tooltips inside.
    * src/xfns.c (Fx_begin_drag): Say that follow-tooltip doesn't
    work with system tooltips.
---
 lisp/mouse.el | 3 +++
 src/xfns.c    | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/lisp/mouse.el b/lisp/mouse.el
index 6a2b1738f7..11014fa1c5 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -3103,6 +3103,9 @@ is copied instead of being cut."
          ;; tooltip.
          (mouse-fine-grained-tracking t)
          (was-tooltip-mode tooltip-mode)
+         ;; System tooltips tend to flicker and in general work
+         ;; incorrectly.
+         (use-system-tooltips nil)
          ;; Whether or not some text was ``cut'' from Emacs to another
          ;; program and the cleaanup code should not try modifying the
          ;; region.
diff --git a/src/xfns.c b/src/xfns.c
index 15e96183e3..43d4d27372 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -6884,7 +6884,8 @@ mouse buttons are released on top of FRAME.
 
 If FOLLOW-TOOLTIP is non-nil, any tooltip currently being displayed
 will be moved to follow the mouse pointer while the drag is in
-progress.
+progress.  Note that this does not work with system tooltips (tooltips
+created when `use-system-tooltips' is non-nil).
 
 This function will sometimes return immediately if no mouse buttons
 are currently held down.  It should only be called when it is known