autoWidth Rendering Garbled

---
title: "autoWidth garbled"
output: flexdashboard::flex_dashboard
---

```{r}
library(tidyverse)
library(DT)
datatable(mtcars %>% as_tibble() %>% select(1:4), 
          options = list(autoWidth = TRUE,
                         columnDefs = list(list(width = '50px', 
                                                targets = "_all"))))
```

The code above is my first attempt at autoWidth within DT and flexdashboard. The code looks correct, yet the output is quite garbled (ie the column headings are not aligned with the column bodies). Tested in Chrome. I imagine IE and Safari won't fare much better. Version Info: [1] DT_0.16 flexdashboard_0.5.2

Start by running the supplied R example with DT 0.16 and flexdashboard 0.5.2 in Chrome, then inspect how the autoWidth and columnDefs options affect the rendered table. Done means the column headings align with their column bodies in the dashboard.