Subject: Re: bug#38038: 27.0.50; Emacs freezes opening tabs.

From: martin rudalics <[email-masked]>
Date: Fri, 8 Nov 2019 10:21:14 +0100

> These hangs occur not only with tab-bar, but also with menu-bar
 > when tab-bar is not enabled.  These hangs can be reproduced by
 > configuring --with-x-toolkit=no and running emacs -Q.
 > Then evaluating this causes hangs:
 >
 >    (set-face-attribute 'menu nil :weight 'ultra-bold :underline t)

On Windows

(set-face-attribute 'default nil :underline t)

suffices to make it hang in the tool bar redisplay code.  I have the
guts feeling that it's related to the new :extend mechanism because it
works in Emacs 26.

martin