bug#66275: 30.0.50; The first line gets invisible when C-g on Android

[Po Lu]

Shingo Tanaka <shingo.fg8@gmail.com> writes:

> Hi,
>
>
> On Android, when (setq visible-bell t) and type C-g (keyboard-quit),
> the first line of the displayed window is overwritten with a white line
> and gets invisible.
>
> Here is how to reproduce.
>
> 1. Run Emacs without init file.
> 2. Goto *scratch* buffer and evaluate (setq visible-bell t)
> 3. Type C-g
> 3. You will see that the first line of *scratch* buffer gets disappeared.

Thanks.  visible-bell is presently nonfunctional under Android,
consequent upon several errors (or, at the minimum, documentation
errors) within Android's drawing primitives.

I will attempt to circumvent these shortcomings; but, given that
visible-bell is a comparatively unused feature, this will not occupy a
position high up my list of priorities.