The bootstrapPage() function does not do anything except load the Bootstrap framework.

Once the framework is loaded, the well panel is now unhelpfully overlapping the right-hand side of the screen; however, it does still resize, as shown in the following screenshot:

Adding a fluid container div around the code makes the user interface, and even the HTML that is produced, exactly the same as in the previous fluidPage() example, as shown in the code snippet:

server = function(input, output){
 
 # server code
}
ui = bootstrapPage(
     div(class = "container-fluid",
 
     fluidRow(
         column(2, wellPanel(p("Column width 2"))),
         column(10, wellPanel(p("Column width 10")))),
     fluidRow(
         column(2, wellPanel(p("Column width 2"))),
         column(10, wellPanel(p("Column width 10")),
             fluidRow(
                 column(6, wellPanel(p("Column width 6"))),
                 column(6, wellPanel(p("Column width 6")))
                     )
             )
         )
     )
)
shinyApp(ui = ui, server = server)

The output of this application looks identical to the nested columns produced by fluidPage(). The HTML that is cogenerated is also the same.