title: Appium (v1.4.16.1), Switch to WebView fails when i try a second time
body: <p>Appium (v1.4.16.1), Switch to WebView fails when I try to switch to webview second time. Is there something I should be considering?</p>
  
  <p>Please refer to the below use case using Appium on Android-</p>
  
  <ol>
  <li>Launch Android Device > Perform some actions</li>
  <li>Switch context = WebView_1 > Perform some actions</li>
  <li>Switch context = Native_App</li>
  <li>Switch context = WebView_1 > Perform some actions</li>
  </ol>
  
  <p>In Step#2 and Step#4, it is the same WebView_1, but the content is different. Say: step#2 opened html-1 and step#4 opened html-2.</p>
  
  <p>Problem: I am unable to switch context in Step#4. </p>
  
  <blockquote>
    <p>.... below are some logs of the error</p>
    
    <blockquote>
      <p>info: [debug] Available contexts: NATIVE_APP,WEBVIEW_1
      info: [debug] Connecting to chrome-backed webview
      info: [debug] Responding to client with error: {"status":13,"value":{"message":"An unknown server-side error occurred while processing the command. (Original error: We already have a chromedriver instance running)","origValue":"We already have a chromedriver instance running"},"sessionId":"38904ff5-928a-4dc0-ac8a-c7bc5f6504e4"}</p>
    </blockquote>
  </blockquote>