In make_lispy_position fix Bug#50993 in rudimentary fashion

* src/keyboard.c (make_lispy_position): Do not set posn to
tool- or tab-bar when track_mouse is enabled (Bug#50993).

src/keyboard.c

@@ -5122,7 +5122,20 @@ make_lispy_position (struct frame *f, Lisp_Object x, Lisp_Object y,
 #endif
       )
     {
-      posn = EQ (window_or_frame, f->tab_bar_window) ? Qtab_bar : Qtool_bar;
+      /* FIXME: While track_mouse is non-nil, we do not report this
+	 event as something that happened on the tool or tab bar since
+	 that would break mouse dragging operations that originate from
+	 an ordinary window beneath and expect the window to auto-scroll
+	 as soon as the mouse cursor appears above or beneath it
+	 (Bug#50993).  Since this "fix" might break track_mouse based
+	 operations originating from the tool or tab bar itself, such
+	 operations should set track_mouse to some special value that
+	 would be recognized by the following check.
+
+	 This issue should be properly handled by 'mouse-drag-track' and
+	 friends, so the below is only a temporary workaround.  */
+      if (NILP (track_mouse))
+	posn = EQ (window_or_frame, f->tab_bar_window) ? Qtab_bar : Qtool_bar;
       /* Kludge alert: for mouse events on the tab bar and tool bar,
 	 keyboard.c wants the frame, not the special-purpose window
 	 we use to display those, and it wants frame-relative