Office Outlook Add-in not opening the compose SourceLocation when redacting a new email

We are building a new Office Add-in for Outlook, but we are not capable of opening the correct SourceLocation when redacting a new email. Our manifest does have the ExtensionPoint for the compose scenario, but every time we create a new email the Read scenario taskpane pops in.

<ExtensionPoint xsi:type="MessageComposeCommandSurface">
  <OfficeTab id="TabDefault">
    <Group id="msgComposeGroup">
      <Label resid="GroupLabel"/>
      <Control xsi:type="Button" id="msgComposeOpenPaneButton">
        <Label resid="ComposeTaskpaneButton.Label"/>
        <Supertip>
          <Title resid="ComposeTaskpaneButton.Label"/>
          <Description resid="ComposeTaskpaneButton.Tooltip"/>
        </Supertip>
        <Icon>
          <bt:Image size="16" resid="icon16"/>
          <bt:Image size="32" resid="icon32"/>
          <bt:Image size="80" resid="icon80"/>
        </Icon>
        <Action xsi:type="ShowTaskpane">
          <SourceLocation resid="ComposeTaskpane.Url"/>
        </Action>
      </Control>
    </Group>
  </OfficeTab>
  </ExtensionPoint>
</DesktopFormFactor>
...
<Resources>
  <bt:Urls>
    <bt:Url id="Taskpane.Url" DefaultValue="https://stackoverflow.com/taskpane.html"/>
    <bt:Url id="ComposeTaskpane.Url" DefaultValue="https://stackoverflow.com/compose.html"/>
  </bt:Urls>
  <bt:ShortStrings>
    <bt:String id="GroupLabel" DefaultValue="TitleName"/>
    <bt:String id="TaskpaneButton.Label" DefaultValue="Taskpane name"/>
    <bt:String id="ComposeTaskpaneButton.Label" DefaultValue="Compose"/>
  </bt:ShortStrings>
  <bt:LongStrings>
    <bt:String id="TaskpaneButton.Tooltip" DefaultValue="Long description"/>
    <bt:String id="ComposeTaskpaneButton.Tooltip" DefaultValue="Long description"/>
  </bt:LongStrings>
</Resources>

Is there any other option of configuration we may need to set in our manifest?

Steps to reproduce:

• Click on New Email and see the compose email view in outlook.
• Click on the icon to open the panel of the Add-in.

Expected to:

• Add-in should open the "compose.html" view, since that's what defined on the ComposeTaskpane.Url id and since the ExtentionPoint is set MessageComposeCommandSurface.

Actual result:

• Add-in opening the "taskpane.html" view, which is defined on the Taskpane.Url id.