bug#50256: thing-at-mouse

[martin rudalics]

> Actually, whereas it fixes the reported issue,
> it breaks everything else: moving point up and down
> always jumps to the fixed column like goal-column,
> selecting a completion from the Completions buffer
> always says "No completion here", 'C-c C-c' in diff-mode
> jumps to the wrong hunk, etc.

Is the below better?

diff --git a/src/window.c b/src/window.c
index cb8fe5fcdb..e86f50e600 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2199,7 +2199,8 @@ DEFUN ("pos-visible-in-window-p", 
Fpos_visible_in_window_p,
     posint = -1;
   else if (!NILP (pos))
     posint = fix_position (pos);
-  else if (w == XWINDOW (selected_window))
+  else if (w == XWINDOW (selected_window)
+          && XBUFFER (w->contents) == current_buffer)
     posint = PT;
   else
     posint = marker_position (w->pointm);

martin