diff --git a/src/diagrams/class/classDb.js b/src/diagrams/class/classDb.js
index d380639eb..cb4c42c8a 100644
--- a/src/diagrams/class/classDb.js
+++ b/src/diagrams/class/classDb.js
@@ -6,16 +6,18 @@ let classes = {};
 /**
  * Function called by parser when a node definition has been found.
  * @param id
+ * @public
  */
 export const addClass = function(id) {
-  if (typeof classes[id] === 'undefined') {
-    classes[id] = {
-      id: id,
-      methods: [],
-      members: [],
-      annotations: []
-    };
-  }
+  // Only add class if not exists
+  if (typeof classes[id] !== 'undefined') return;
+
+  classes[id] = {
+    id: id,
+    methods: [],
+    members: [],
+    annotations: []
+  };
 };
 
 export const clear = function() {
@@ -41,15 +43,34 @@ export const addRelation = function(relation) {
   relations.push(relation);
 };
 
+/**
+ * Adds an annotation to the specified class
+ * Annotations mark special properties of the given type (like 'interface' or 'service')
+ * @param className The class name
+ * @param annotation The name of the annotation without any brackets
+ * @public
+ */
 export const addAnnotation = function(className, annotation) {
   classes[className].annotations.push(annotation);
 };
 
+/**
+ * Adds a member to the specified class
+ * @param className The class name
+ * @param member The full name of the member.
+ * If the member is enclosed in <<brackets>> it is treated as an annotation
+ * If the member is ending with a closing bracket ) it is treated as a method
+ * Otherwise the member will be treated as a normal property
+ * @public
+ */
 export const addMember = function(className, member) {
   const theClass = classes[className];
   if (typeof member === 'string') {
+    // Member can contain white spaces, we trim them out
     const memberString = member.trim();
+
     if (memberString.startsWith('<<') && memberString.endsWith('>>')) {
+      // Remove leading and trailing brackets
       theClass.annotations.push(memberString.substring(2, memberString.length - 2));
     } else if (memberString.endsWith(')')) {
       theClass.methods.push(memberString);
diff --git a/src/diagrams/class/classRenderer.js b/src/diagrams/class/classRenderer.js
index 2ee1f0087..2d0825edc 100644
--- a/src/diagrams/class/classRenderer.js
+++ b/src/diagrams/class/classRenderer.js
@@ -255,10 +255,13 @@ const drawClass = function(elem, classDef) {
     height: 0
   };
 
+  // add class group
   const g = elem
     .append('g')
     .attr('id', id)
     .attr('class', 'classGroup');
+
+  // add title
   const title = g
     .append('text')
     .attr('y', conf.textHeight + conf.padding)
@@ -278,6 +281,7 @@ const drawClass = function(elem, classDef) {
     .text(classDef.id)
     .attr('class', 'title');
 
+  // If class has annotations the title needs to have an offset of the text height
   if (!isFirst) classTitle.attr('dy', conf.textHeight);
 
   const titleHeight = title.node().getBBox().height;
@@ -324,21 +328,25 @@ const drawClass = function(elem, classDef) {
   });
 
   const classBox = g.node().getBBox();
-  g.insert('rect', ':first-child')
+  const rect = g
+    .insert('rect', ':first-child')
     .attr('x', 0)
     .attr('y', 0)
     .attr('width', classBox.width + 2 * conf.padding)
     .attr('height', classBox.height + conf.padding + 0.5 * conf.dividerMargin);
 
+  const rectWidth = rect.node().getBBox().width;
+
   // Center title
+  // We subtract the width of each text element from the class box width and divide it by 2
   title.node().childNodes.forEach(function(x) {
-    x.setAttribute('x', (classBox.width + 2 * conf.padding - x.getBBox().width) / 2);
+    x.setAttribute('x', (rectWidth - x.getBBox().width) / 2);
   });
 
-  membersLine.attr('x2', classBox.width + 2 * conf.padding);
-  methodsLine.attr('x2', classBox.width + 2 * conf.padding);
+  membersLine.attr('x2', rectWidth);
+  methodsLine.attr('x2', rectWidth);
 
-  classInfo.width = classBox.width + 2 * conf.padding;
+  classInfo.width = rectWidth;
   classInfo.height = classBox.height + conf.padding + 0.5 * conf.dividerMargin;
 
   idCache[id] = classInfo;