(redisplay_window): Don't automatically select a new window

start for a contination line during mouse-click.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index b018735c3c6..07762f56582 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -13134,8 +13134,15 @@ redisplay_window (window, just_this_one_p)
 
       /* If first window line is a continuation line, and window start
          is inside the modified region, but the first change is before
-         current window start, we must select a new window start.*/
+         current window start, we must select a new window start.
+
+         However, if this is the result of a down-mouse event (e.g. by
+         extending the mouse-drag-overlay), we don't want to select a
+         new window start, since that would change the position under
+         the mouse, resulting in an unwanted mouse-movement rather
+         than a simple mouse-click.  */
       if (NILP (w->start_at_line_beg)
+          && NILP (do_mouse_tracking)
           && CHARPOS (startp) > BEGV)
         {
           /* Make sure beg_unchanged and end_unchanged are up to date.