Hello Dmitry,

is the attached patch fix this issue for you?

Thanks.

Dmitry Gutov <dmitry@gutov.dev> writes:

> Set up:
>
> (defun split-window-prefer-side-by-side (&optional window)
>   (let ((split-height-threshold (and (< (window-width window)
>                                         split-width-threshold)
>                                      split-height-threshold)))
>     (split-window-sensibly window)))
>
> (setq split-window-preferred-function 'split-window-prefer-side-by-side)
>
> Split the frame, e.g. 'C-x 3'.
>
> Then create some register (e.g. using 'C-x r C-@') and then invoke
> another command reading it. E.g. 'C-x r j'.
>
> Wait the necessary 1 second for the preview to appear - it will use one
> of the existing windows to show the list of registers.
>
> Then, whether you choose the register, or C-g out of the choice, the
> window used to display the list will be deleted.
>
> Previously mentioned in bug#66394.
>
> Not a regression on master, just reproduced it in 29.
>
>
>
>

-- 
Thierry