title: How to access all activate tk window IDs (path names) in R console?
body: <p>Suppose I create several tk windows but do not assign them to any real objects.</p>
  <pre><code>library(tcltk)
  # two activated tk windows
  tcl('toplevel',&quot;.foo&quot;)
  tcl('toplevel',&quot;.bar&quot;)
  </code></pre>
  <p>Is it possible to access their IDs (or path names) by executing some function <code>f()</code> so that two &quot;tclObj&quot; objects are returned or a string (<code>c(&quot;.foo&quot;, &quot;.bar&quot;)</code>) could be returned?</p>