GTK4: letterspacing, signscolumn off #21002

Steps to reproduce

⬅️ gtk4 ... ➡️ gtk3

It might have gotten a lot better since last time I took a close look, but you can clearly see the:

• letterspacing is stretched.
• ⬅️ signs column has border

Expected behaviour

Match gtk3

Version of Vim

9.2.0927

Environment

Operating system: OpenSUSE Tumbleweed

Logs and stack traces