Excel add-on, manifest, shared JavaScript runtime, can`t define <Runtimes> element

We are developing an Excel add-on and trying to make it 'working long'. Now it starts to work when its tab is opened, but we would like to run it when the document is loaded and then keep add-on working. As I understood, this approach can help: https://docs.microsoft.com/en-us/office/dev/add-ins/develop/configure-your-add-in-to-use-a-shared-runtime

bu when I start to define the manifest:

...
<Hosts>
      <Host xsi:type="Workbook">
        <Runtimes>
          <Runtime resid="KI.Taskpane.UrlMain" lifetime="long" />
        </Runtimes>
        
        <DesktopFormFactor>
        ...

and then 'publish' the manifest - MS VS 2017 reports the error:

The element 'Host' in namespace 'http://schemas.microsoft.com/office/taskpaneappversionoverrides' has invalid child element 'Runtimes' in namespace 'http://schemas.microsoft.com/office/taskpaneappversionoverrides'.

List of possible elements expected: 'DesktopFormFactor' in namespace 'http://schemas.microsoft.com/office/taskpaneappversionoverrides'.

What can I do to fix it? thanks for suggestions.

PS: here is MS Doc about 'runtimes' https://docs.microsoft.com/ru-ru/office/dev/add-ins/reference/manifest/runtimes

PPS: did ask same question at 

https://stackoverflow.com/questions/66588639/excel-add-on-manifest-shared-javascript-runtime-cant-define-runtimes-eleme