title: Fill area for different series in highcharter for opposite directions
body: <p>So I have 5 series all between -1 and 1, 4 of those series are boundries.  I want to plot the bottom two series (i.e the two that are between 0 and -1) with their area filled down to the x-axis foot. Then exactly the opposite for the two series (between 0 an +1) filled up to the x-axis head. While the last series is just a line that ossilates between them.</p>
  <p>I tried splitting the 4 area series in to two opposite y-axis in order to change the plotoption.  However, the last plot option adjustment keeps overriding the first one.  Any help or suggestion would be appreciated.</p>
  <p>Target output:</p>
  <p><img src="https://i.stack.imgur.com/JWJrP.png" alt="Target output" /></p>
  <p>Current output:</p>
  <p><img src="https://i.stack.imgur.com/1zlhz.png" alt="Current output" /></p>
  <pre><code>library(tidyverse)
  library(timetk)
  library(kableExtra)
  library(highcharter)
  
  datetime&lt;-seq(
    from = floor_date(as.Date(&quot;2021-07-01&quot;), unit = &quot;month&quot;),
    to = ceiling_date(Sys.Date(), &quot;month&quot;) - 1,
    by = &quot;month&quot;
  )
  
  mascore&lt;- runif(12, -1, 1)
  
  mod_over&lt;- runif(12, 0.25,1)
  str_over&lt;- runif(12, 0.1, 0.25)
  mod_under&lt;- runif(12, -1, -0.25)
  str_under&lt;- runif(12, -0.25, -0.1)
  
  
  highcharter::highchart() %&gt;%
    highcharter::hc_xAxis(categories = datetime) %&gt;% 
    highcharter::hc_yAxis_multiples(
    list(reversed= FALSE,max=1,min=-1,startOnTick= FALSE, endOnTick= FALSE ),
    list(opposite=TRUE,max=1,min=-1,startOnTick= FALSE, endOnTick= FALSE )
    ) %&gt;%
    highcharter::hc_add_series(mod_over,
                               name = &quot;Moderate Overweight&quot;,
                               type=&quot;spline&quot;,
                               color='#47648E',
                               yAxis=1) %&gt;%
    highcharter::hc_add_series(str_over,
                               name = &quot;Strong Overweight&quot;,
                               type=&quot;areaspline&quot;,
                               color='#002855',
                               yAxis=1) %&gt;%
    highcharter::hc_plotOptions(
                              areaspline = list(
                                fillOpacity= 0.5,
                                threshold= 1,
                                yAxis=1
                              )
    ) %&gt;% 
    
    highcharter::hc_add_series(mod_under,
                               name = &quot;Moderate Underweight&quot;,
                               type=&quot;areaspline&quot;,
                               color='#D1948A',
                               yAxis=0) %&gt;%
    highcharter::hc_add_series(str_under,
                               name = &quot;Strong Underweight&quot;,
                               type=&quot;areaspline&quot;,
                               color='#C26E60',
                               yAxis=0) %&gt;%
    
    highcharter::hc_plotOptions(
                          areaspline = list(
                            fillOpacity= 0.5,
                            threshold= -1,
                            yAxis=1
                              )
                            ) %&gt;% 
    
    highcharter::hc_add_series(mascore,
                               name = &quot;MAScore&quot;,
                               type=&quot;spline&quot;,
                               color=&quot;black&quot;,
                               lineWidth=5,
                               yAxis=0) %&gt;%
    
    highcharter::hc_exporting(enabled = TRUE) 
  </code></pre>