Fix region extension when scroll bar is on the right

 src/keyboard.c (make_lispy_position): When the click is on the
 right-side vertical scroll bar, pass the rightmost X coordinate to
 buffer_posn_from_coords, so that the returned text position
 reflects the closest point to the click.  Fixes region extension
 when mouse moves outside the Emacs frame that has scroll bars on
 the right.

2 files changed, 18 insertions, 6 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index cfef5c46d1a..ae827cb4416 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2015-03-05  Eli Zaretskii  <eliz@gnu.org>
+
+        * keyboard.c (make_lispy_position): When the click is on the
+        right-side vertical scroll bar, pass the rightmost X coordinate to
+        buffer_posn_from_coords, so that the returned text position
+        reflects the closest point to the click.  Fixes region extension
+        when mouse moves outside the Emacs frame that has scroll bars on
+        the right.
+
 2015-03-04  Martin Rudalics  <rudalics@gmx.at>
 
         * frame.c (x_set_font): Try to keep frame height and width
diff --git a/src/keyboard.c b/src/keyboard.c
index e1c5691324d..bf65df1584c 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -5360,9 +5360,9 @@ make_lispy_position (struct frame *f, Lisp_Object x, Lisp_Object y,
           dy = yret = wy;
         }
 
-      /* For clicks in the text area, fringes, or margins, call
-         buffer_posn_from_coords to extract TEXTPOS, the buffer
-         position nearest to the click.  */
+      /* For clicks in the text area, fringes, margins, or vertical
+         scroll bar, call buffer_posn_from_coords to extract TEXTPOS,
+         the buffer position nearest to the click.  */
       if (!textpos)
         {
           Lisp_Object string2, object2 = Qnil;
@@ -5370,11 +5370,14 @@ make_lispy_position (struct frame *f, Lisp_Object x, Lisp_Object y,
           int dx2, dy2;
           int width2, height2;
           /* The pixel X coordinate passed to buffer_posn_from_coords
-             is the X coordinate relative to the text area for
-             text-area and right-margin clicks, zero otherwise.  */
+             is the X coordinate relative to the text area for clicks
+             in text-area, right-margin/fringe and right-side vertical
+             scroll bar, zero otherwise.  */
           int x2
             = (part == ON_TEXT) ? xret
-            : (part == ON_RIGHT_FRINGE || part == ON_RIGHT_MARGIN)
+            : (part == ON_RIGHT_FRINGE || part == ON_RIGHT_MARGIN
+               || (part == ON_VERTICAL_SCROLL_BAR
+                   && WINDOW_HAS_VERTICAL_SCROLL_BAR_ON_RIGHT (w)))
             ? (XINT (x) - window_box_left (w, TEXT_AREA))
             : 0;
           int y2 = wy;