title: Close Extension window automatically after sending transaction
body: <p>When you use the Maiar Exchange with the Chrome Extension and send a transaction, you can see that the extension window automatically closes after sending the transaction.</p>
  <p>When I implement the same behavior, the Extension window stays open and the sendTransaction() Promise only resolves after the call is done. If I close the window by myself by clicking somewhere else on the website, I get the following error in the console:</p>
  <pre><code>Uncaught (in promise) Extension window was closed without response.
  </code></pre>
  <p>With that error, my promise success resolving code is not executed anymore which basically forces the user to wait about 30 seconds until the transaction is done.</p>
  <p>This happens when using the <code>sendTransaction()</code> method of the ExtensionProvider from erdjs.</p>
  <p>Does anyone have an explanation how e.g. the Maiar Exchange solves this?</p>