Libre Office issue with tab_spanner

[peterejkemp]

Description

table spanners work perfectly in html and pdf format, but the word document output loses the domain of the span when using libre office. Office 365 and Google Docs seem OK as well.

Reproducible example

---
title: "test"
format: docx
---

```{r}
library(gt)
tbl_comp_names <- structure(list(lvl = c("BEBRAS", "Advent of code"), 
                                 per = c(79.5,
                                         37.2), 
                                 per_grand = c(57.4, 26.9), 
                                 grandtotal = c(108L, 108L), 
                                 total = c(78L, 78L)), 
                            row.names = c(NA, -2L), 
                            class = c("tbl_df", 
                                      "tbl", "data.frame"))

tbl_comp_names %>% 
  gt() %>%
  tab_spanner(
    columns = starts_with("per"),
    label=("percentage")) %>%
  tab_spanner(
    columns = ends_with("total"),
    label=("n"))

```

Expected result

The span appears like this in RStudio:

But in docx (libre office), it appears like this:

Session info

R version 4.4.1 (2024-06-14 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 11 x64 (build 22631)

Matrix products: default

locale:
[1] LC_COLLATE=English_United Kingdom.utf8 LC_CTYPE=English_United Kingdom.utf8
[3] LC_MONETARY=English_United Kingdom.utf8 LC_NUMERIC=C
[5] LC_TIME=English_United Kingdom.utf8

time zone: Europe/London
tzcode source: internal

attached base packages:
[1] stats graphics grDevices utils datasets methods base

other attached packages:
[1] gt_0.11.0 ggtext_0.1.2 janitor_2.2.0 arrow_17.0.0.1 openxlsx_4.2.7.1 labelled_2.13.0
[7] here_1.0.1 haven_2.5.4 glue_1.7.0 lubridate_1.9.3 forcats_1.0.0 stringr_1.5.1
[13] dplyr_1.1.4 purrr_1.0.2 readr_2.1.5 tidyr_1.3.1 tibble_3.2.1 ggplot2_3.5.1
[19] tidyverse_2.0.0

loaded via a namespace (and not attached):
[1] sass_0.4.9 utf8_1.2.4 generics_0.1.3 xml2_1.3.6 stringi_1.8.4
[6] hms_1.1.3 digest_0.6.37 magrittr_2.0.3 grid_4.4.1 timechange_0.3.0
[11] fastmap_1.2.0 rprojroot_2.0.4 zip_2.3.1 fansi_1.0.6 scales_1.3.0
[16] cli_3.6.3 crayon_1.5.3 rlang_1.1.4 bit64_4.5.2 munsell_0.5.1
[21] withr_3.0.1 tools_4.4.1 tzdb_0.4.0 colorspace_2.1-1 assertthat_0.2.1
[26] vctrs_0.6.5 R6_2.5.1 lifecycle_1.0.4 snakecase_0.11.1 bit_4.5.0
[31] vroom_1.6.5 pkgconfig_2.0.3 pillar_1.9.0 gtable_0.3.5 Rcpp_1.0.13
[36] xfun_0.47 tidyselect_1.2.1 knitr_1.48 rstudioapi_0.16.0 htmltools_0.5.8.1
[41] compiler_4.4.1 gridtext_0.1.5