diff --git a/src/redux/preview.js b/src/redux/preview.js
index e115cdd3c..a151fe41c 100644
--- a/src/redux/preview.js
+++ b/src/redux/preview.js
@@ -87,6 +87,19 @@ module.exports.previewReducer = (state, action) => {
             comments: [...state.comments, ...action.items] // TODO: consider a different way of doing this?
         });
     case 'SET_COMMENT_DELETED':
+        if (action.topLevelCommentId) {
+            return Object.assign({}, state, {
+                replies: Object.assign({}, state.replies, {
+                    [action.topLevelCommentId]: state.replies[action.topLevelCommentId].map(comment => {
+                        if (comment.id === action.commentId) {
+                            return Object.assign({}, comment, {deleted: true});
+                        }
+                        return comment;
+                    })
+                })
+            });
+        }
+
         return Object.assign({}, state, {
             comments: state.comments.map(comment => {
                 if (comment.id === action.commentId) {
@@ -96,30 +109,13 @@ module.exports.previewReducer = (state, action) => {
             })
         });
     case 'ADD_NEW_COMMENT':
-        if (action.comment.parent_id) {
-            let topLevelParent = action.comment.parent_id;
-
-            // If this is a nested reply, we need to look up which top level comment
-            // to put this new reply under.
-            if (!state.replies[topLevelParent]) {
-                Object.keys(state.replies).forEach(topLevelCommentId => {
-                    state.replies[topLevelCommentId].forEach(reply => {
-                        if (reply.id === action.comment.parent_id) {
-                            topLevelParent = topLevelCommentId;
-                        }
-                    });
-                });
-            }
-
-            if (state.replies[topLevelParent]) {
-                const replies = JSON.parse(JSON.stringify(state.replies));
-                // Replies to comments go at the end  of the thread
-                replies[topLevelParent] = replies[topLevelParent].concat(action.comment);
-                return Object.assign({}, state, {replies: replies});
-            }
-
-            log.error('Could not find top level parent to put reply in');
-            return state;
+        if (action.topLevelCommentId) {
+            return Object.assign({}, state, {
+                replies: Object.assign({}, state.replies, {
+                    // Replies to comments go at the end  of the thread
+                    [action.topLevelCommentId]: state.replies[action.topLevelCommentId].concat(action.comment)
+                })
+            });
         }
 
         // Reply to the top level project, put the reply at the beginning
@@ -232,14 +228,16 @@ module.exports.setStudioFetchStatus = (studioId, status) => ({
     status: status
 });
 
-module.exports.setCommentDeleted = commentId => ({
+module.exports.setCommentDeleted = (commentId, topLevelCommentId) => ({
     type: 'SET_COMMENT_DELETED',
-    commentId: commentId
+    commentId: commentId,
+    topLevelCommentId: topLevelCommentId
 });
 
-module.exports.addNewComment = comment => ({
+module.exports.addNewComment = (comment, topLevelCommentId) => ({
     type: 'ADD_NEW_COMMENT',
-    comment: comment
+    comment: comment,
+    topLevelCommentId: topLevelCommentId
 });
 
 module.exports.getProjectInfo = (id, token) => (dispatch => {
diff --git a/src/views/preview/comment/comment.jsx b/src/views/preview/comment/comment.jsx
index 25b0a9f94..378a76b24 100644
--- a/src/views/preview/comment/comment.jsx
+++ b/src/views/preview/comment/comment.jsx
@@ -15,6 +15,7 @@ class Comment extends React.Component {
         super(props);
 
         bindAll(this, [
+            'handleDelete',
             'handlePostReply',
             'handleToggleReplying'
         ]);
@@ -33,6 +34,10 @@ class Comment extends React.Component {
         this.setState({replying: !this.state.replying});
     }
 
+    handleDelete () {
+        this.props.onDelete(this.props.id);
+    }
+
     render () {
         const {
             author,
@@ -41,7 +46,6 @@ class Comment extends React.Component {
             canReply,
             content,
             datetimeCreated,
-            onDelete,
             id,
             projectId
         } = this.props;
@@ -64,7 +68,7 @@ class Comment extends React.Component {
                             {deletable ? (
                                 <span
                                     className="comment-delete"
-                                    onClick={onDelete}
+                                    onClick={this.handleDelete}
                                 >
                                     Delete {/* TODO internationalize */}
                                 </span>
diff --git a/src/views/preview/comment/top-level-comment.jsx b/src/views/preview/comment/top-level-comment.jsx
index 77a2bed28..1f0899970 100644
--- a/src/views/preview/comment/top-level-comment.jsx
+++ b/src/views/preview/comment/top-level-comment.jsx
@@ -13,7 +13,8 @@ class TopLevelComment extends React.Component {
         super(props);
         bindAll(this, [
             'handleExpandThread',
-            'handleDelete'
+            'handleAddComment',
+            'handleDeleteComment'
         ]);
         this.state = {
             expanded: false
@@ -26,8 +27,14 @@ class TopLevelComment extends React.Component {
         });
     }
 
-    handleDelete () {
-        this.props.onDelete(this.props.id);
+    handleDeleteReply (commentId) {
+        // Only apply topLevelCommentId for deleting replies
+        // The top level comment itself just gets passed onDelete directly
+        this.props.onDelete(commentId, this.props.id);
+    }
+
+    handleAddComment (comment) {
+        this.props.onAddComment(comment, this.props.id);
     }
 
     render () {
@@ -39,18 +46,17 @@ class TopLevelComment extends React.Component {
             deletable,
             deleted,
             id,
+            onDelete,
             replies,
-            projectId,
-            onAddComment
+            projectId
         } = this.props;
 
         return (
             <FlexRow className="comment-container">
                 <Comment
                     projectId={projectId}
-                    onAddComment={onAddComment}
-                    onDelete={this.handleDelete}
-                    {...{author, content, datetimeCreated, deletable, deleted, canReply, id}}
+                    onAddComment={this.handleAddComment}
+                    {...{author, content, datetimeCreated, deletable, deleted, canReply, id, onDelete}}
                 />
                 {replies.length > 0 &&
                     <FlexRow
@@ -72,8 +78,8 @@ class TopLevelComment extends React.Component {
                                 id={reply.id}
                                 key={reply.id}
                                 projectId={projectId}
-                                onAddComment={this.props.onAddComment}
-                                onDelete={this.handleDelete}
+                                onAddComment={this.handleAddComment}
+                                onDelete={this.handleDeleteReply}
                             />
                         ))}
                     </FlexRow>
diff --git a/src/views/preview/preview.jsx b/src/views/preview/preview.jsx
index a4ea7d051..76ed08b89 100644
--- a/src/views/preview/preview.jsx
+++ b/src/views/preview/preview.jsx
@@ -167,11 +167,11 @@ class Preview extends React.Component {
                 });
             });
     }
-    handleAddComment (comment) {
-        this.props.handleAddComment(comment);
+    handleAddComment (comment, topLevelCommentId) {
+        this.props.handleAddComment(comment, topLevelCommentId);
     }
-    handleDeleteComment (id) {
-        this.props.handleDeleteComment(this.state.projectId, id, this.props.user.token);
+    handleDeleteComment (id, topLevelCommentId) {
+        this.props.handleDeleteComment(this.state.projectId, id, topLevelCommentId, this.props.user.token);
     }
     handleReportClick () {
         this.setState({reportOpen: true});
@@ -532,11 +532,11 @@ const mapStateToProps = state => {
 };
 
 const mapDispatchToProps = dispatch => ({
-    handleAddComment: comment => {
-        dispatch(previewActions.addNewComment(comment));
+    handleAddComment: (comment, topLevelCommentId) => {
+        dispatch(previewActions.addNewComment(comment, topLevelCommentId));
     },
-    handleDeleteComment: (projectId, commentId, token) => {
-        dispatch(previewActions.deleteComment(projectId, commentId, token));
+    handleDeleteComment: (projectId, commentId, topLevelCommentId, token) => {
+        dispatch(previewActions.deleteComment(projectId, commentId, topLevelCommentId, token));
     },
     handleOpenRegistration: event => {
         event.preventDefault();