title: How do I make stable displaying multiple dygraphs in one shiny?
body: <p>I am using 2 R dygraphs  in one Shiny App. I observe a problem returning the graphs, that is, sometimes it doesn't load/display one of the dygraphs, sometimes it does. Weird behaviour. Anyone experienced something similar?</p>
  
  <p>Contexts:</p>
  
  <p>ui</p>
  
  <pre><code>library(zoo)
  library(dygraphs) 
  
  ...
  tabName="time",
    fluidRow(
      tabBox(width = 350,
             tabPanel(title="Product", dygraphOutput("dygraph1")),
             tabPanel(title="Segment", dygraphOutput("dygraph2")) 
  ...
  </code></pre>
  
  <p>server</p>
  
  <pre><code>  })
  
    zoo&lt;-structure(c(2252L, 2256L, 2256L, 2257L, 2259L, 2262L, 2262L, 
                  2262L, 765L, 767L, 767L, 769L, 768L, 769L, 774L, 706L, 
                  16239L, 16220L, 26184L, 26148L, 26091L, 26099L, 26118L, 
                  12607L), .Dim = c(8L, 3L), .Dimnames = list(NULL, c("A", 
                  "B", "C")), index = structure(c(16849, 16853, 16854, 
                  16855, 16856, 16857, 16858, 16859), class = "Date"), class =     
                  "zoo")
  
    zoo2&lt;-structure(c(52L, 56L, 56L, 57L, 59L, 62L, 62L, 
                   62L, 65L, 67L, 67L, 69L, 68L, 69L, 74L, 76L, 
                   162L, 162L, 261L, 261L, 260L, 260L, 261L, 
                   126L), .Dim = c(8L, 3L), .Dimnames = list(NULL, c("D", "E",             
                   "F")), index = structure(c(16849, 16853, 16854,16855,  
                   16856, 16857, 16858, 16859), class = "Date"), class = "zoo")
  
    output$dygraph1&lt;-renderDygraph({
      dygraph(zoo)%&gt;%
      dyOptions(stackedGraph = TRUE, drawGrid = FALSE) %&gt;%
      dyRangeSelector(height = 20)%&gt;%
      dyHighlight(highlightSeriesOpts = list(strokeWidth = 3))
  
    })
  
    output$dygraph2&lt;-renderDygraph({
      dygraph(zoo2) %&gt;%
      dyOptions(stackedGraph = TRUE,drawGrid = FALSE) %&gt;%
      dyRangeSelector(height = 20) %&gt;%
      dyHighlight(highlightSeriesOpts = list(strokeWidth = 3))
  
    })
  </code></pre>
  
  <p>I am running R Studio v. 0.99.484, R v. 3.2.3, Windows Machine, Dygraphs Package v. 0.7</p>