Subject: bug#39649: 27.0.60; tab-line doesn't scroll

From: Lars Ingebrigtsen <[email-masked]>
Date: Sun, 20 Sep 2020 10:40:09 +0200

Juri Linkov <[email-masked]> writes:

> But the bug creeps in only when there is space between tabs:
>
> (format-mode-line (concat " " (propertize "tab1" 'face
> 'tab-line-tab-current) " x"))
> #(" tab1 x" 1 5 (face tab-line-tab-current))
>
> (format-mode-line (concat " " (propertize "tab1" 'face
> 'tab-line-tab-current) " x") 'tab-line)
> #(" tab1 x" 0 1 (face tab-line) 1 5 (face tab-line) 5 7 (face tab-line))
>
> Here the face 'tab-line' overwrites the face 'tab-line-tab-current'.

The mode-line formatting machinery doesn't support having a mixture of
text properties over a single string -- for efficiency, it assumes that
the same properties are used over the entire string.  If you want
something else, you unfortunately have to use :propertize or a list of
strings.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no