Only enable an 'idea' as a drop target in Grouping Stage

web/static/js/components/idea.jsx

@@ -5,6 +5,7 @@ import { connect } from "react-redux"
 import { bindActionCreators } from "redux"
 import values from "lodash/values"
 
+import STAGES from "../configs/stages"
 import IdeaEditForm from "./idea_edit_form"
 import IdeaDropTarget from "./idea_drop_target"
 import IdeaLiveEditContent from "./idea_live_edit_content"
@@ -44,6 +45,7 @@ export const Idea = props => {
   return (
     <IdeaDropTarget
       tagName="li"
+      dragAndDropHandlersActive={stage === STAGES.GROUPING}
       wrapperClassName={classes}
       onDropOfIdea={() => {}}
       title={idea.body}