Custom action in Header Bar
I am trying to build a custom action in headerbar of aem editor and i was able to populate it below the "Start workflow" menu. But the question here is where to add the dialog or code for the custom action which looks similar to Start workflow popup.
After research i came to know that "Start Workflow" popup is coming from /libs/cq/gui/components/authoring/workflow which is being refered at /libs/wcm/core/content/editor/jcr:content/content/items/content/content/items/startworkflowmodal.
I tried similar to this for my custom action and i am getting the below error:
org.apache.sling.servlets.get.impl.DefaultGetServlet No renderer for extension html, cannot render resource MergedResource
Any Suggestion on what i am missing and please let me know if this is correct approach. Thanks In advance.

