Emacs: How to remove wave underline in lsp header-line?

Question

I'm not sure what it is for but it's a bit annoying and not helpful.

How to remove that wave underline?

Answer 1

Using

(setq lsp-headerline-breadcrumb-enable-diagnostics nil)

moves them away.

Answer 2

You can override the related face somewhere in your emacs init process by adding:

(set-face-underline 'lsp-headerline-breadcrumb-path-warning-face nil)

---

In case you want to remove other underlines, add these too:

(set-face-underline 'lsp-headerline-breadcrumb-symbols-hint-face nil)
(set-face-underline 'lsp-headerline-breadcrumb-symbols-info-face nil)
(set-face-underline 'lsp-headerline-breadcrumb-path-hint-face nil)
(set-face-underline 'lsp-headerline-breadcrumb-path-info-face nil)

Headerline settings

Answer 3

In addition to what @Nikita said, you can simply customize any such faces, using M-x customize-face (and save the customization).

The wavy underline is just one possible face attribute - it's trivial to change/unset it.

Faces are user preferences, just like options (user variables). And Customize is a clean, safe way to set and save your preferences.

By default preferences are saved to your Emacs init file, but it's generally better to have Customize save settings instead to the file that's named by the value of variable custom-file. That way, Customize never touches your init file, which you reserve for your own Elisp code.