Using the latest bslib with flexdashboard, I believe the bootstrap css flex property for navbar messes with the navbar layout as it forces all flex elements to have the same width.
Reprex:
---
title: "Break Line"
author: "meztez"
output:
flexdashboard::flex_dashboard:
orientation: rows
vertical_layout: fill
theme:
version: 4
bootswatch: cosmo
primary: "#003366"
runtime: shiny_prerendered
---
Mercury
=====================================
Venus
=====================================
Earth
=====================================
Mars
=====================================
Jupiter
=====================================
Uranus
=====================================
Neptune
=====================================
Pluto
=====================================


Switching theme to cosmo still works fine
Using the latest bslib with flexdashboard, I believe the bootstrap css flex property for navbar messes with the navbar layout as it forces all flex elements to have the same width.
Reprex:
Switching theme to cosmo still works fine