Unable to customize navlistPanel() header styles

shiny
1

Is there a way to customize the appearance of headers in a navlistPanel()? I would normally do that with tags$span() or something similar, but anything other than plain text seems to render in the main content, not the menu. Is this a bug?

library(shiny)

ui <- fluidPage(
  navlistPanel(
    tabPanel("Tab 1", "Content 1"),
    tabPanel("Tab 2", "Content 2"),
    # Plain text works - only appears in menu
    "GOOD: This appears in menu",
    tabPanel("Tab 3", "Content 3"),
    # bug? this adds a weird space to the menu and appears in main content
    tags$span("Bad: This span appears in main content"),
    tabPanel("Tab 4", "Content 4")
  )
)

server <- function(input, output, session) { }

shinyApp(ui, server)
2

What is your expected result? Would you like to style the titles of the tabPanels? Otherwise, running your code provides us with a meaningful warning:

Warning message:
Navigation containers expect a collection of bslib::nav_panel()/shiny::tabPanel()s and/or bslib::nav_menu()/shiny::navbarMenu()s. Consider using header or footer if you wish to place content above (or below) every panel's contents.