title: Auto-opening side-loaded taskpane
body: <p>Is it possible to auto-open plugins that are in developer mode?</p>
  
  <p>According to <a href="https://docs.microsoft.com/en-us/office/dev/add-ins/develop/automatically-open-a-task-pane-with-a-document" rel="nofollow noreferrer">documentation</a></p>
  
  <blockquote>
    <p>The pane that you designate to open automatically <strong>will only open if
    the add-in is already installed on the user's device</strong>. If the user does
    not have the add-in installed when they open a document, the autoopen
    feature will not work and the setting will be ignored. If you also
    require the add-in to be distributed with the document you need to set
    the visibility property to 1; this can only be done using OpenXML, an
    example is provided later in this article.</p>
  </blockquote>
  
  <p>In particular, the file i'm attempting to auto-open is what based off <a href="https://github.com/OfficeDev/generator-office" rel="nofollow noreferrer">office-generator</a> with a single modification:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8" standalone="yes"?&gt;
    &lt;we:webextension xmlns:we="http://schemas.microsoft.com/office/webextensions/webextension/2010/11" id="{acbc717b-5139-428a-9089-e9d6d7d8affc}"&gt;
    &lt;we:reference id="acbc717b-5139-428a-9089-e9d6d7d8affc" version="1.0.0.0" store="developer" storeType="Registry"/&gt;
    &lt;we:alternateReferences/&gt;
  
    &lt;we:properties&gt;
      &lt;we:property name="Office.AutoShowTaskpaneWithDocument" value="true"/&gt;
    &lt;/we:properties&gt;
  
    &lt;we:bindings/&gt;
    &lt;we:snapshot xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"/&gt;
  &lt;/we:webextension&gt;
  </code></pre>
  
  <p>with the addition of <code>&lt;we:property name="Office.AutoShowTaskpaneWithDocument" value="true"/&gt;</code></p>
  
  <p>and by modifying <code>manifest.xml</code> as follows:</p>
  
  <pre><code>&lt;Action xsi:type="ShowTaskpane"&gt;
    &lt;TaskpaneId&gt;Office.AutoShowTaskpaneWithDocument&lt;/TaskpaneId&gt;
    &lt;SourceLocation resid="Taskpane.Url"/&gt;
  &lt;/Action&gt;
  </code></pre>
  
  <p><strong>Problem:</strong></p>
  
  <p>It is expected that there would be one taskpane which would be opened automatically.</p>
  
  <p>The task pane that was opened automatically has an error which states that <code>we can't find the task pane to open</code>. On the other hand, clicking on the ribbon allows the task pane to open as per normal, side by side with the broken auto-opened task pane as shown in the image below:</p>
  
  <p><a href="https://i.stack.imgur.com/4iOxg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4iOxg.png" alt="enter image description here"></a></p>