title: Error in installing packages 'RGtk2' and 'rattle' in R
body: <p>I tried to install R packages 'rattle' but when I typed</p>
  
  <pre><code>install.packages('rattle')
  </code></pre>
  
  <p>it returns</p>
  
  <pre><code>Warning in install.packages :
  dependency ‘RGtk2’ is not available
  </code></pre>
  
  <p>So I tried install 'RGtk2',</p>
  
  <pre><code>install.packages('RGtk2')
  </code></pre>
  
  <p>it returns</p>
  
  <pre><code>Warning in install.packages :
  package ‘RGtk2’ is not available (for R version 3.2.3)
  </code></pre>
  
  <p>My computer is windows 8.1, R version 3.2.3 and I'm working on the R studio.</p>