Fixed in
https://github.com/rstudio/shiny/commit/85baa596d08793c453fc8d55d124cfd5baacda13


On Sat, Dec 14, 2013 at 4:57 PM, Yihui Xie <notifications@github.com> wrote:

> In R/bootstrap-layout.R:
>
> > +#'     mainPanel(
> > +#'       plotOutput("distPlot")
> > +#'     )
> > +#'   )
> > +#' ))
> > +#'
> > +#' @export
> > +sidebarLayout <- function(sidebarPanel,
> > +                          mainPanel,
> > +                          position = c("left", "right"),
> > +                          fluid = TRUE,
> > +                          widths = c(4, 8)) {
> > +
> > +  # validate that inputs were created by their respective functions
> > +  validateSpan(sidebarPanel, "sidebarPanel", widths[[1]])
> > +  validateSpan(mainPanel, "mainPanel", widths[[2]])
>
> I guess we should remove the widths argument here, because it is use only
> for the validation purpose; it does not really specify the widths of the
> two panels, which can be confusing. I did not realize this until I tried sidebarLayout(widths
> = c(3, 9), sidebarPanel(...), mainPanel(...)) which gave an error message
> that I did not understand at first. Now I know I should use column(3, ...)and column(9,
> ...) here. If the users have specified the column width via column(n, ...),
> I guess there is no need to ask them to provide the widths argument in
> sidebarLayout() just to verify themselves, i.e. this seems awkward
>
> sidebarLayout(widths = c(3, 6),
>   column(3, fooInput...),
>   column(6, barInput...))
>
> I'd rather just write
>
> sidebarLayout(
>   column(3, fooInput...),
>   column(6, barInput...))
>
> As users learn more about fluidRow()/fixedRow(), they will probably stop
> using sidebarLayout, and naturally transit to
>
> fluidRow(
>   column(3, fooInput...),
>   column(6, barInput...))
>
> Without the widths argument, the transition will also be easier.
>
> —
> Reply to this email directly or view it on GitHub<https://github.com/rstudio/shiny/pull/327/files#r8353246>
> .
>