Don't allow tooltips to be transient for override redirect windows

* src/xfns.c (Fx_show_tip): Delete WM_TRANSIENT_FOR if the child
window is override-redirect.

* src/xterm.c (x_term_init): Intern new atom.
* src/xterm.h (struct x_display_info): New atom
`Xatom_wm_transient_for'.

src/xfns.c

@@ -7788,6 +7788,7 @@ Text larger than the specified size is clipped.  */)
   ptrdiff_t count_1;
   Lisp_Object window, size, tip_buf;
   Window child;
+  XWindowAttributes child_attrs;
   int dest_x_return, dest_y_return;
   AUTO_STRING (tip, " *tip*");
 
@@ -8028,11 +8029,24 @@ Text larger than the specified size is clipped.  */)
 			     FRAME_DISPLAY_INFO (f)->root_window,
 			     root_x, root_y, &dest_x_return,
 			     &dest_y_return, &child))
-    XSetTransientForHint (FRAME_X_DISPLAY (tip_f),
-			  FRAME_X_WINDOW (tip_f), child);
+    {
+      /* But only if the child is not override-redirect, which can
+	 happen if the pointer is above a menu.  */
+
+      if (XGetWindowAttributes (FRAME_X_DISPLAY (f),
+				child, &child_attrs)
+	  || child_attrs.override_redirect)
+	XDeleteProperty (FRAME_X_DISPLAY (tip_f),
+			 FRAME_X_WINDOW (tip_f),
+			 FRAME_DISPLAY_INFO (tip_f)->Xatom_wm_transient_for);
+      else
+	XSetTransientForHint (FRAME_X_DISPLAY (tip_f),
+			      FRAME_X_WINDOW (tip_f), child);
+    }
   else
-    XSetTransientForHint (FRAME_X_DISPLAY (tip_f),
-			  FRAME_X_WINDOW (tip_f), None);
+    XDeleteProperty (FRAME_X_DISPLAY (tip_f),
+		     FRAME_X_WINDOW (tip_f),
+		     FRAME_DISPLAY_INFO (tip_f)->Xatom_wm_transient_for);
 
 #ifndef USE_XCB
   XMoveResizeWindow (FRAME_X_DISPLAY (tip_f), FRAME_X_WINDOW (tip_f),

src/xterm.c

@@ -15984,6 +15984,7 @@ x_term_init (Lisp_Object display_name, char *xrm_option, char *resource_name)
       ATOM_REFS_INIT ("WM_CONFIGURE_DENIED", Xatom_wm_configure_denied)
       ATOM_REFS_INIT ("WM_MOVED", Xatom_wm_window_moved)
       ATOM_REFS_INIT ("WM_CLIENT_LEADER", Xatom_wm_client_leader)
+      ATOM_REFS_INIT ("WM_TRANSIENT_FOR", Xatom_wm_transient_for)
       ATOM_REFS_INIT ("Editres", Xatom_editres)
       ATOM_REFS_INIT ("CLIPBOARD", Xatom_CLIPBOARD)
       ATOM_REFS_INIT ("TIMESTAMP", Xatom_TIMESTAMP)

src/xterm.h

@@ -364,6 +364,8 @@ struct x_display_info
   Atom Xatom_wm_configure_denied; /* When our config request is denied */
   Atom Xatom_wm_window_moved;     /* When the WM moves us.  */
   Atom Xatom_wm_client_leader;    /* Id of client leader window.  */
+  Atom Xatom_wm_transient_for;    /* Id of whatever window we are
+				     transient for. */
 
   /* EditRes protocol */
   Atom Xatom_editres;