bug#55970: 29.0.50; Emacs crashes when dragging the scroll bar with "--with-pgtk" and "--without-toolkit-scroll-bars" configure flags

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> OK, but please explain how come the code in pgtk_send_scroll_bar_event
> leaves the modifiers unset, and that is still OK, notwithstanding the
> code in keyboard.c that expects either up or down modifier for any
> mouse click event?  Isn't that a bug regardless?

The mouse click code that expects an up or down modifier is only used
for scroll bar events when USE_TOOLKIT_SCROLL_BARS isn't defined.  The
code actually used with toolkit scroll bars starts at line 6359 of
keyboard.c.