title: R leaflet search marker NOT work
body: <p>I was able to use these 2 packages to search the markers on the map. However, I just installed them on my new computer again, but the search button does not work now. How to search markers?
  Thank you</p>
  
  <pre><code># We need latest leaflet package from Github, as CRAN package is too old.
  devtools::install_github('rstudio/leaflet')
  devtools::install_github('bhaskarvk/leaflet.extras')
  library("leaflet")
  library("leaflet.extras")
  
  cities &lt;- read.csv(textConnection("
  City,Lat,Long,Pop
                                Boston,42.3601,-71.0589,645966
                                Hartford,41.7627,-72.6743,125017
                                New York City,40.7127,-74.0059,8406000
                                Philadelphia,39.9500,-75.1667,1553000
                                Pittsburgh,40.4397,-79.9764,305841
                                Providence,41.8236,-71.4222,177994
                                "))
  
  leaflet(cities) %&gt;% addProviderTiles(providers$OpenStreetMap) %&gt;%
  addCircleMarkers(lng = ~Long, lat = ~Lat, weight = 1, fillOpacity=0.5,
                 radius = ~sqrt(Pop)/50 , popup = ~City, label=~City, group 
  ='cities') %&gt;%
  addResetMapButton() %&gt;%
  addSearchFeatures(
  targetGroups = 'cities',
  options = searchFeaturesOptions(
    zoom=12, openPopup = TRUE, firstTipSubmit = TRUE,
    autoCollapse = TRUE, hideMarkerOnCollapse = TRUE )) %&gt;%
  addControl("&lt;P&gt;&lt;B&gt;Hint!&lt;/B&gt; Search for ...&lt;br/&gt;&lt;ul&gt;&lt;li&gt;New York&lt;/li&gt; 
  &lt;li&gt;Boston&lt;/li&gt;&lt;li&gt;Hartford&lt;/li&gt;&lt;li&gt;Philadelphia&lt;/li&gt;&lt;li&gt;Pittsburgh&lt;/li&gt; 
  &lt;li&gt;Providence&lt;/li&gt;&lt;/ul&gt;&lt;/P&gt;",
           position='bottomright')
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/1ha7H.png" alt="SS of Search Bar"></p>