bug#46557: 28.0.50; Visual glitches in text mode when tab-bar visibility is altered at load time

[Juri Linkov]

This bug can't be reproduced anymore, maybe it's already fixed?

> The following recipe creates a broken visual appearance of emacs in text
> mode, at least on GNU/Linux:
>
> 1) Create a test.el file with these lines:
>
> (set-frame-parameter nil 'tab-bar-lines 0)
> (set-frame-parameter nil 'tab-bar-lines 1)
> (set-frame-parameter nil 'tab-bar-lines 0)
>
> 2) Start emacs in text mode with:
> emacs -nw -Q -l test.el
>
> 3) Create a few tabs with "C-x t 2"
>
> The menu-bar is not showing after emacs starts. In addition, tabs start
> to appear in two lines. Other visual artifacts (lines jumping around for
> example) will become apparent after using emacs for a while.
>
> In the real world this problem appeared because I had customized a
> variable (tab-bar-select-tab-modifiers) that ran:
>
> (tab-bar-mode -1)
> (tab-bar-mode 1)
>
> in its :set function.