Velocity scripts in component methods should not change $doc

Steps to reproduce:

1. create an event listener in a wiki page as explained in https://extensions.xwiki.org/xwiki/bin/view/Extension/WikiComponent%20Module#HImplementingmethods ; the listner should listen to DocumentUpdatingEvent at least.
2. instead of a groovy macro use a velocity macro in the method code body, like

   {{velocity}}
    ##
   {{/velocity}}

   (The comment symbols are important, a wholly empty velocity code block does not reproduce the issue

1. go to and "AppWithinMinutes" generated application, and click on "Edit Application" (I tried this with the pre-installed "Movies" Application: http://localhost:8080/xwiki/wiki/subwiki1/view/Help/Applications/Movies/
2. in the "Step 2 — Structure your data" do not update anything, just click "Next Step"

Expected behavior:

• the next step ("Step 3 — Locate your data") should be shown

Actually observed:

• a different page is shown, with the page name of the event handler page, appended by TemplateProvider

(Instead of implementing the event listener you can also import the attached xar: Sandbox.Surprise.xar )

The problem seems to occur because the velocity macro is executed in a velocity context shared with the velocity code of the page AppWithinMinutes.ClassEditSheet in the #macro(updateAndSaveClass)

  ##
  ## Save
  ##
  #if(!$errorMessage)
    #set($discard = $xdoc.setXClass($xclass))
    #set($discard = $xdoc.renameProperties($doc.documentReference, $fieldsToRename))
    #set($discard = $xdoc.setHidden(true))
    #set($discard = $xdoc.setMetaDataDirty(true))
    ####  here before the save $doc points to the class under edit
    #set($discard = $doc.save($services.localization.render('core.comment.updateClassProperty'), $minorEdit))
    ####  here after the save $doc points to the event listener page 
 #end

(Comments starting with #### are inserted by me and not part of the platform code.)

Obvious workaround: do not use velocity macros for event listeners in wiki pages, but use groovy-macros (you need programming rights anyway.)