Unexpected fill-ability differences between navset_tab and navset_bar
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Priority: Medium
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Description
Describe the problem
I was trying to get my tables inside navset_tab panels to fill the containers, but they will not.
After some trial and error, I find that navset_bar panels behave differently and in a more expected fashion.
I created this vignette to show the difference. You can see the "big table" tab of the "navset_tab test" is the one that has unexpected behavior - its DT table only fills half the card.
Apologies if this is expected behavior and is a result of my misunderstanding. I have the impression that the tabs and bars are meant to be visual differences and that the intended behavior of bootstrap cards is to fill their contents.
Thanks for the great package!
# dependencies ----
library(tidyverse)
library(shiny)
library(bslib)
library(DT)
# functions ----
# forgive the overloading
datatable <- function(data, options = list(paging = FALSE, scrollY = "100%", dom = "t"), ...) {
data |>
DT::datatable(
rownames = FALSE,
fillContainer = TRUE, # important; allows frozen header
options = options,
...
)
}
# data ----
dat <- mtcars |>
as_tibble() |>
list() |>
rep(5) |>
list_rbind()
# user interface ----
ui <- page_navbar(
nav_panel(
"navset_bar test",
card(
navset_bar(
nav_panel("small table", DTOutput("small_table_for_bar")),
nav_panel("big table", textOutput("message_bar"), DTOutput("big_table_for_bar"))
)
)
),
nav_panel(
"navset_tab test",
card(
navset_tab(
nav_panel("small table", DTOutput("small_table_for_tab")),
nav_panel("big table", textOutput("message_tab"), DTOutput("big_table_for_tab"))
)
)
)
)
# server ----
server <- function(input, output, session) {
output$small_table_for_bar <- renderDT(datatable(dat[1:5, ]))
output$big_table_for_bar <- renderDT(datatable(dat))
output$message_bar <- renderText("the contents fill the card")
output$small_table_for_tab <- renderDT(datatable(dat[1:5, ]))
output$big_table_for_tab <- renderDT(datatable(dat))
output$message_tab <- renderText("the contents no NOT fill the card")
}
# launch ---
shinyApp(ui = ui, server = server)
Session Info
> devtools::session_info()
─ Session info ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
setting value
version R version 4.5.3 (2026-03-11 ucrt)
os Windows 11 x64 (build 26200)
system x86_64, mingw32
ui RStudio
language (EN)
collate English_United States.utf8
ctype English_United States.utf8
tz America/New_York
date 2026-07-15
rstudio 2026.04.0+526 Globemaster Allium (desktop)
pandoc NA
quarto ERROR: Unknown command "TMPDIR=C:/Users/st2516/AppData/Local/Temp/RtmpeUFV7e/file40dcdcb2996". Did you mean command "install"? @ C:\\PROGRA~1\\Quarto\\bin\\quarto.exe
─ Packages ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
package * version date (UTC) lib source
bit 4.6.0 2025-03-06 [1] CRAN (R 4.5.3)
bit64 4.8.0 2026-04-21 [1] CRAN (R 4.5.3)
blend * 0.0.0.9000 2026-07-13 [1] local
blob 1.3.0 2026-01-14 [1] CRAN (R 4.5.3)
bsicons 0.1.2 2023-11-04 [1] CRAN (R 4.5.3)
bslib * 0.10.0 2026-01-26 [1] CRAN (R 4.5.3)
cachem 1.1.0 2024-05-16 [1] CRAN (R 4.5.3)
cellranger 1.1.0 2016-07-27 [1] CRAN (R 4.5.3)
cli 3.6.6 2026-04-09 [1] CRAN (R 4.5.3)
crayon 1.5.3 2024-06-20 [1] CRAN (R 4.5.3)
crosstalk 1.2.2 2025-08-26 [1] CRAN (R 4.5.3)
DBI * 1.3.0 2026-02-25 [1] CRAN (R 4.5.3)
dbplyr * 2.5.2 2026-02-13 [1] CRAN (R 4.5.3)
devtools 2.5.2 2026-04-30 [1] CRAN (R 4.5.3)
digest 0.6.39 2025-11-19 [1] CRAN (R 4.5.3)
dplyr * 1.2.1 2026-04-03 [1] CRAN (R 4.5.3)
DT * 0.34.0 2025-09-02 [1] CRAN (R 4.5.3)
duckdb * 1.5.2 2026-04-13 [1] CRAN (R 4.5.3)
ellipsis 0.3.3 2026-04-04 [1] CRAN (R 4.5.3)
farver 2.1.2 2024-05-13 [1] CRAN (R 4.5.3)
fastmap 1.2.0 2024-05-15 [1] CRAN (R 4.5.3)
fontawesome * 0.5.3 2024-11-16 [1] CRAN (R 4.5.3)
forcats * 1.0.1 2025-09-25 [1] CRAN (R 4.5.3)
fs 2.1.0 2026-04-18 [1] CRAN (R 4.5.3)
generics 0.1.4 2025-05-09 [1] CRAN (R 4.5.3)
ggplot2 * 4.0.3 2026-04-22 [1] CRAN (R 4.5.3)
ggsci * 5.0.0 2026-04-17 [1] CRAN (R 4.5.3)
glue 1.8.1 2026-04-17 [1] CRAN (R 4.5.3)
gtable 0.3.6 2024-10-25 [1] CRAN (R 4.5.3)
hms 1.1.4 2025-10-17 [1] CRAN (R 4.5.3)
htmltools * 0.5.9 2025-12-04 [1] CRAN (R 4.5.3)
htmlwidgets 1.6.4 2023-12-06 [1] CRAN (R 4.5.3)
httpuv 1.6.17 2026-03-18 [1] CRAN (R 4.5.3)
janitor * 2.2.1 2024-12-22 [1] RSPM
jquerylib 0.1.4 2021-04-26 [1] CRAN (R 4.5.3)
jsonlite 2.0.0 2025-03-27 [1] CRAN (R 4.5.3)
later 1.4.8 2026-03-05 [1] CRAN (R 4.5.3)
lifecycle 1.0.5 2026-01-08 [1] CRAN (R 4.5.3)
lpSolve 5.6.23 2024-12-14 [1] CRAN (R 4.5.2)
lubridate * 1.9.5 2026-02-04 [1] CRAN (R 4.5.3)
magrittr 2.0.5 2026-04-04 [1] CRAN (R 4.5.3)
memoise 2.0.1 2021-11-26 [1] CRAN (R 4.5.3)
mime 0.13 2025-03-17 [1] CRAN (R 4.5.2)
odbc * 1.7.0 2026-05-09 [1] CRAN (R 4.5.3)
otel 0.2.0 2025-08-29 [1] CRAN (R 4.5.3)
pillar 1.11.1 2025-09-17 [1] CRAN (R 4.5.3)
pkgbuild 1.4.8 2025-05-26 [1] CRAN (R 4.5.3)
pkgconfig 2.0.3 2019-09-22 [1] CRAN (R 4.5.3)
pkgload 1.5.2 2026-04-22 [1] CRAN (R 4.5.3)
promises 1.5.0 2025-11-01 [1] CRAN (R 4.5.3)
purrr * 1.2.2 2026-04-10 [1] CRAN (R 4.5.3)
R6 2.6.1 2025-02-15 [1] CRAN (R 4.5.3)
RColorBrewer 1.1-3 2022-04-03 [1] CRAN (R 4.5.2)
Rcpp 1.1.1-1.1 2026-04-24 [1] CRAN (R 4.5.3)
reactable * 0.4.5 2025-12-01 [1] CRAN (R 4.5.3)
reactR 0.6.1 2024-09-14 [1] CRAN (R 4.5.3)
readr * 2.2.0 2026-02-19 [1] CRAN (R 4.5.3)
readxl * 1.4.5 2025-03-07 [1] CRAN (R 4.5.3)
rlang 1.2.0 2026-04-06 [1] CRAN (R 4.5.3)
rsconnect 1.10.0 2026-06-08 [1] CRAN (R 4.5.3)
rstudioapi 0.18.0 2026-01-16 [1] CRAN (R 4.5.3)
S7 0.2.2 2026-04-22 [1] CRAN (R 4.5.3)
sass 0.4.10 2025-04-11 [1] CRAN (R 4.5.3)
scales 1.4.0 2025-04-24 [1] CRAN (R 4.5.3)
sessioninfo 1.2.3 2025-02-05 [1] CRAN (R 4.5.3)
shiny * 1.13.0 2026-02-20 [1] CRAN (R 4.5.3)
snakecase 0.11.1 2023-08-27 [1] CRAN (R 4.5.3)
sourcetools 0.1.7-2 2026-03-28 [1] CRAN (R 4.5.3)
stringi 1.8.7 2025-03-27 [1] CRAN (R 4.5.2)
stringr * 1.6.0 2025-11-04 [1] CRAN (R 4.5.3)
tibble * 3.3.1 2026-01-11 [1] CRAN (R 4.5.3)
tidyr * 1.3.2 2025-12-19 [1] CRAN (R 4.5.3)
tidyselect 1.2.1 2024-03-11 [1] CRAN (R 4.5.3)
tidyverse * 2.0.0 2023-02-22 [1] CRAN (R 4.5.3)
timechange 0.4.0 2026-01-29 [1] CRAN (R 4.5.3)
tzdb 0.5.0 2025-03-15 [1] CRAN (R 4.5.3)
usethis 3.2.1 2025-09-06 [1] CRAN (R 4.5.3)
utf8 1.2.6 2025-06-08 [1] CRAN (R 4.5.3)
vctrs 0.7.3 2026-04-11 [1] CRAN (R 4.5.3)
vroom 1.7.1 2026-03-31 [1] CRAN (R 4.5.3)
withr 3.0.2 2024-10-28 [1] CRAN (R 4.5.3)
writexl * 1.5.4 2025-04-15 [1] CRAN (R 4.5.3)
xtable 1.8-8 2026-02-22 [1] CRAN (R 4.5.3)
yaml 2.3.12 2025-12-10 [1] CRAN (R 4.5.3)
[1] C:/Users/st2516/AppData/Local/R/win-library/4.5
[2] C:/Program Files/R/R-4.5.3/library
* ── Packages attached to the search path.
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running the supplied Shiny app and comparing the navset_tab and navset_bar table panels. Read the bslib navigation and card styling involved in their fill behavior; done means the DT table fills the card consistently in both examples.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- bootstrap, r, sass
- Domain
- frontend, web-dev
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100