title: How does one set the background color of a multiplot-figure created via grid.arrange() in an R-shinydashboard?
body: <p><strong>Description:</strong></p>
  
  <p>Here is a screenshot of my dashboard that I created with the shiny-package in R. It simply contains a static multiplot (via ggplot and grid.arrange).</p>
  
  <p><a href="https://i.stack.imgur.com/nEEso.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nEEso.png" alt="Shiny Dashboard with unwanted white areas."></a></p>
  
  <p><strong>Problem:</strong></p>
  
  <p>There are white areas in the figure which I want to be grey. Just as the background. I have to use grid.arrange to produce the figure.</p>
  
  <p><strong>Question:</strong></p>
  
  <p>How do I need to change the code to make the white areas grey? The code is attached below.</p>
  
  <pre><code>library(shiny)
  library(grid)
  library(gridExtra)
  library(plyr)
  library(dplyr)
  library(tidyr)
  library(ggplot2)
  library(DT)
  library(shinydashboard)
  library(bubbles)
  require(igraph)
  require(rCharts)
  library(formattable)
  library(networkD3)
  library(shinyjs)
  data(MisLinks)
  data(MisNodes)
  
  
  
  
  ui=dashboardPage(
    #skin = "black",
  
    dashboardHeader(title =  "MyTitle"),
  
    dashboardSidebar(
     "nothing here"
  
  
  
    ),
  
  
    # Show a plot of the generated distribution
   dashboardBody(
  
                    plotOutput("meinPiePlot")
  
                    )
  )
  
  
  
  
  server=function(input,output,session){
  
  
  
     output$meinPiePlot=renderPlot({
  
  
  
     Plot01=ggplot(NULL, aes(x="", y=mtcars$qsec, fill=mtcars$disp))+
     geom_bar(width = 1, stat = "identity")+
      coord_polar("y", start=0.8)+
      theme(plot.background = element_rect(fill = "#ECF0F5",
                                 colour = "#ECF0F5",
                                  linetype = "solid"),
  
              strip.background= element_rect(fill = "green",
                                  colour = "green",
                                  size = 0.5, linetype = "solid"),                    
  
  
              panel.background=element_rect(fill = "#ECF0F5",
                                 colour = "#ECF0F5"),
              #aspect.ratio = 1 / 1.4,
              axis.text.x=element_blank(),
              legend.position="none"
                                  )
  
         Plot02=ggplot(NULL, aes(x="", y=mtcars$disp, fill=mtcars$mpg))+
     geom_bar(width = 1, stat = "identity")+
      coord_polar("y", start=0.8)+
      theme(plot.background = element_rect(fill = "#ECF0F5",
                                 colour = "#ECF0F5",
                                  linetype = "solid"),
  
              strip.background= element_rect(fill = "green",
                                  colour = "green",
                                  size = 0.5, linetype = "solid"),                    
  
  
              panel.background=element_rect(fill = "#ECF0F5",
                                 colour = "#ECF0F5"),
              #aspect.ratio = 1 / 1.4,
              axis.text.x=element_blank(),
              legend.position="none"
                                  )
  
      grid.arrange(Plot01,Plot02, ncol=2)
  
  
  
      })
  
  
  
  }
  
  shinyApp(ui, server)
  </code></pre>