title: How to get Leaflet for R use 100% of Shiny dashboard height
body: <p>I am in the process of creating a Shiny dashboard application, where the dashboard body is supposed to show some maps. So far no problem to get the map expand over the entire width of the body, but it's somehow not willing to adjust to the full height.
  <a href="https://i.stack.imgur.com/jxEEI.png"><img src="https://i.stack.imgur.com/jxEEI.png" alt="enter image description here"></a></p>
  
  <p>The leaflet itself is already set to cover 100% of the height, but it doesn't do the trick. As soon as I use the height attribute for the leafletOutput the leaflet object will not show at all, and I am left with an empty box.</p>
  
  <p>The code can be found below:</p>
  
  <pre><code>library(shinydashboard)
  library(leaflet)
  
  ui &lt;- dashboardPage(
    dashboardHeader(title = "Basic dashboard"),
    dashboardSidebar(
      sidebarMenu(
        menuItem(
          "Maps", 
          tabName = "maps", 
          icon = icon("globe"),
          menuSubItem("Watersheds", tabName = "m_water", icon = icon("map")),
          menuSubItem("Population", tabName = "m_pop", icon = icon("map"))
        ),
        menuItem(
          "Charts", 
          tabName = "charts", 
          icon = icon("bar-chart"),
          menuSubItem("Watersheds", tabName = "c_water", icon = icon("area-chart")),
          menuSubItem("Population", tabName = "c_pop", icon = icon("area-chart"))
        )
      )
    ),
    dashboardBody(
      tabItems(
        tabItem(
          tabName = "m_water",
          box(
            title = "Baltic catchment areas",
            collapsible = TRUE,
            width = "100%",
            height = "100%",
            leafletOutput("l_watershed")
          )
        ),
        tabItem(
          tabName = "m_pop",
          # Map in Dashboard
          leafletOutput("l_population")
        ),
        tabItem(
          tabName = "charts",
          h2("Second tab content")
        )
      )
    )
  )
  
  server &lt;- function(input, output) {
    set.seed(122)
    histdata &lt;- rnorm(500)
  
    output$l_watershed &lt;- renderLeaflet({
      leaflet(height = "100%") %&gt;% addTiles() %&gt;% setView(19.08, 60.25, zoom = 4) %&gt;%addWMSTiles(
        "http://62.236.121.188/arcgis/services/DataAndMaps/Background/MapServer/WMSServer?",
        layers = "11",
        options = WMSTileOptions(
          format = "image/png",
          transparent = TRUE
        ),
        attribution = "Catchment area provided by HELCOM"
      )
    })
  
    output$l_population &lt;- renderLeaflet({
      leaflet(height = "100%") %&gt;% addTiles() %&gt;% setView(19.08, 60.25, zoom = 4) %&gt;%addWMSTiles(
        "http://62.236.121.188/arcgis/services/DataAndMaps/Background/MapServer/WMSServer?",
        layers = "17",
        options = WMSTileOptions(
          format = "image/png",
          transparent = TRUE
        ),
        attribution = "Population data provided by HELCOM"
      )
    })
  }
  
  shinyApp(ui, server)
  </code></pre>