Shiny app in vignette works with browseVignettes() but not vignette() in RStudio

I've created a Shiny app to demonstrate package functionality and hosted it on I used knitr::include_app() to embed it in the package vignette, and built a pkgdown site.

Now, if you view the vignette on the pkgdown site, the app displays as intended (second panel if you scroll down):

If you run the following code locally, you can view the vignette in your browser and the app displays as intended:


However, if you run this code, the vignette opens in the RStudio viewer pane and the app does not load as desired:

vignette('testshiny', package = 'testShinyVignette')

Is this the intended behavior or am I doing something wrong? Source code for the vignette is at