闪亮的radioButton未显示

Question

所以我提出了一个带有一些单选按钮和滑块的Shiny应用程序，如下所示：

library(shiny)

shinyUI(fluidPage(

  titlePanel("test"),

  sidebarLayout(
    sidebarPanel(
      sliderInput("smplSize", "Number of samples:", min = 10, max = 500, value = 250),
      hr(),
      radioButtons("pType", 
                   label = "Choose plot type:", 
                   choices = c("Normal" = "norm", "t-dist" = "tdist"), 
                  inline = T),
      sliderInput("mean", "Value for mean:", min = 0, max = 10, value = 0),
      sliderInput("sd", "Value for sd:", min = 0.1, max = 5, value = 1),
      sliderInput("df", "Degrees of freedom:", min = 1, max = 50, value = 1),
      hr()
    ),

    mainPanel(
      plotOutput("normalDist2")
    )
  )
))

当我运行应用程序时，一切正常，但是，我看不到单选按钮，但我能够选择它们并server.R响应我的更改......

我拍了一张应用的截图：

如您所见，圆圈未显示，但是，通过点击标签，我可以修改server.R中编码的绘图输出

sessionInfo()的输出：

R version 3.1.2 (2014-10-31)
Platform: x86_64-apple-darwin13.4.0 (64-bit)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

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

other attached packages:
 [1] reshape2_1.4.1  rmarkdown_0.9.5 knitr_1.12.3    heatmap3_1.1.1  ggthemes_3.0.2  gridExtra_2.2.1
 [7] tidyr_0.4.1     dplyr_0.4.3     ggplot2_2.1.0   shiny_0.13.1   

loaded via a namespace (and not attached):
 [1] assertthat_0.1     colorspace_1.2-6   DBI_0.3.1          digest_0.6.9       fastcluster_1.1.16
 [6] grid_3.1.2         gtable_0.2.0       htmltools_0.3      httpuv_1.3.3       jsonlite_0.9.19   
[11] labeling_0.3       magrittr_1.5       mime_0.4           munsell_0.4.3      parallel_3.1.2    
[16] plyr_1.8.3         R6_2.1.2           Rcpp_0.12.3        scales_0.4.0       stringi_1.0-1     
[21] stringr_1.0.0      tools_3.1.2        xtable_1.8-2