Re: Run `M-x list-input-methods` and then scroll down the screen in input method panel using the mouse or arrow key will cause Emacs unresponsive for about 1 minite.

[Eli Zaretskii]

[Please don't cross-post here and in help-gnu-emacs, choose just one.]

> From: Hongyi Zhao <hongyi.zhao@gmail.com>
> Date: Sat, 19 Jun 2021 13:05:57 +0800
> 
> I noticed the following strange problem:
> 
> First start Emacs like this:
> 
> $ /usr/local/bin/emacs -Q
> 
> Then run `M-x list-input-methods` and scroll down the screen in input
> method panel using the mouse or arrow key will cause Emacs
> unresponsive for about 1 minute.

It isn't necessarily strange: Emacs looks for the fonts needed to
display the relevant characters, so if you have a lot of fonts
installed, and some character is not supported, it will take Emacs a
lot of time to scan all those fonts.