diff --git a/gen/__init__.py b/gen/__init__.py
index 1b8da9e..e05b8ee 100644
--- a/gen/__init__.py
+++ b/gen/__init__.py
@@ -12,6 +12,7 @@ import appy.pod
 from appy.pod.renderer import Renderer
 from appy.shared.data import countries
 from appy.shared.xml_parser import XhtmlCleaner
+from appy.shared.diff import HtmlDiff
 from appy.shared.utils import Traceback, getOsTempFolder, formatNumber, \
                               FileWrapper, sequenceTypes
 
@@ -678,8 +679,9 @@ class Type:
             layouts['view'].addCssClasses('focus')
             layouts['edit'].addCssClasses('focus')
         # If layouts are the default ones, set width=None instead of width=100%
-        # for the field if it is not in a group.
-        if areDefault and not self.group:
+        # for the field if it is not in a group (excepted for rich texts).
+        if areDefault and not self.group and \
+           not ((self.type == 'String') and (self.format == String.XHTML)):
             for layoutType in layouts.iterkeys():
                 layouts[layoutType].width = ''
         # Remove letters "r" from the layouts if the field is not required.
@@ -765,10 +767,12 @@ class Type:
                 return self.default
         return value
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         '''p_value is a real p_obj(ect) value from a field from this type. This
            method returns a pretty, string-formatted version, for displaying
-           purposes. Needs to be overridden by some child classes.'''
+           purposes. Needs to be overridden by some child classes. If
+           p_showChanges is True, the result must also include the changes that
+           occurred on p_value across the ages.'''
         if self.isEmptyValue(value): return ''
         return value
 
@@ -971,7 +975,7 @@ class Integer(Type):
     def getStorableValue(self, value):
         if not self.isEmptyValue(value): return self.pythonType(value)
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         if self.isEmptyValue(value): return ''
         return str(value)
 
@@ -1009,7 +1013,7 @@ class Float(Type):
                       label, sdefault, scolspan)
         self.pythonType = float
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         return formatNumber(value, sep=self.sep[0], precision=self.precision,
                             tsep=self.tsep)
 
@@ -1214,7 +1218,7 @@ class String(Type):
                 view = 'lc-f'
             else:
                 view = 'l-f'
-            return {'view': view, 'edit': 'lrv-d-f'}
+            return {'view': Table(view, width='100%'), 'edit': 'lrv-d-f'}
         elif self.isMultiValued():
             return {'view': 'l-f', 'edit': 'lrv-f'}
 
@@ -1246,7 +1250,31 @@ class String(Type):
                         type='warning')
         Type.store(self, obj, value)
 
-    def getFormattedValue(self, obj, value):
+    def getDiffValue(self, obj, value):
+        '''Returns a version of p_value that includes the cumulative diffs
+           between  successive versions.'''
+        res = None
+        lastEvent = None
+        for event in obj.workflow_history.values()[0]:
+            if event['action'] != '_datachange_': continue
+            if self.name not in event['changes']: continue
+            if res == None:
+                # We have found the first version of the field
+                res = event['changes'][self.name][0] or ''
+            else:
+                # We need to produce the difference between current result and
+                # this version.
+                iMsg, dMsg = obj.getHistoryTexts(lastEvent)
+                thisVersion = event['changes'][self.name][0] or ''
+                comparator = HtmlDiff(res, thisVersion, iMsg, dMsg)
+                res = comparator.get()
+            lastEvent = event
+        # Now we need to compare the result with the current version.
+        iMsg, dMsg = obj.getHistoryTexts(lastEvent)
+        comparator = HtmlDiff(res, value or '', iMsg, dMsg)
+        return comparator.get()
+
+    def getFormattedValue(self, obj, value, showChanges=False):
         if self.isEmptyValue(value): return ''
         res = value
         if self.isSelect:
@@ -1265,6 +1293,9 @@ class String(Type):
                     res = [t('%s_list_%s' % (self.labelId, v)) for v in value]
                 else:
                     res = t('%s_list_%s' % (self.labelId, value))
+        elif (self.format == String.XHTML) and showChanges:
+            # Compute the successive changes that occurred on p_value.
+            res = self.getDiffValue(obj, res)
         # If value starts with a carriage return, add a space; else, it will
         # be ignored.
         if isinstance(res, basestring) and \
@@ -1477,7 +1508,7 @@ class Boolean(Type):
         if value == None: return False
         return value
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         if value: res = obj.translate('yes')
         else:     res = obj.translate('no')
         return res
@@ -1542,7 +1573,7 @@ class Date(Type):
         except DateTime.DateError, ValueError:
             return obj.translate('bad_date')
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         if self.isEmptyValue(value): return ''
         tool = obj.getTool().appy()
         # A problem may occur with some extreme year values. Replace the "year"
@@ -1621,7 +1652,7 @@ class File(Type):
         if value: value = FileWrapper(value)
         return value
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         if not value: return value
         return value._zopeFile
 
@@ -1901,7 +1932,7 @@ class Ref(Type):
         if someObjects: return res
         return res.objects
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         return value
 
     def getIndexType(self): return 'ListIndex'
@@ -2142,7 +2173,7 @@ class Computed(Type):
             # self.method is a method that will return the field value
             return self.callMethod(obj, self.method, raiseOnError=True)
 
-    def getFormattedValue(self, obj, value):
+    def getFormattedValue(self, obj, value, showChanges=False):
         if not isinstance(value, basestring): return str(value)
         return value
 
diff --git a/gen/mixins/__init__.py b/gen/mixins/__init__.py
index 6749602..cfbcf6e 100644
--- a/gen/mixins/__init__.py
+++ b/gen/mixins/__init__.py
@@ -514,10 +514,10 @@ class BaseMixin:
             listType = self.getAppyType(listName)
             return listType.getInnerValue(outerValue, name, int(i))
 
-    def getFormattedFieldValue(self, name, value):
+    def getFormattedFieldValue(self, name, value, showChanges):
         '''Gets a nice, string representation of p_value which is a value from
            field named p_name.'''
-        return self.getAppyType(name).getFormattedValue(self, value)
+        return self.getAppyType(name).getFormattedValue(self,value,showChanges)
 
     def getRequestFieldValue(self, name):
         '''Gets the value of field p_name as may be present in the request.'''
@@ -991,15 +991,6 @@ class BaseMixin:
             return 1
         return 0
 
-    def hasHistory(self):
-        '''Has this object an history?'''
-        if hasattr(self.aq_base, 'workflow_history') and self.workflow_history:
-            key = self.workflow_history.keys()[0]
-            for event in self.workflow_history[key]:
-                if event['action'] and (event['comments'] != '_invisible_'):
-                    return True
-        return False
-
     def findNewValue(self, field, history, stopIndex):
         '''This function tries to find a more recent version of value of p_field
            on p_self. It first tries to find it in history[:stopIndex+1]. If
@@ -1027,6 +1018,20 @@ class BaseMixin:
             res.append(msg.encode('utf-8'))
         return res
 
+    def hasHistory(self, fieldName=None):
+        '''Has this object an history? If p_fieldName is specified, the question
+           becomes: has this object an history for field p_fieldName?'''
+        if hasattr(self.aq_base, 'workflow_history') and self.workflow_history:
+            history = self.workflow_history.values()[0]
+            if not fieldName:
+                for event in history:
+                    if event['action'] and (event['comments'] != '_invisible_'):
+                        return True
+            else:
+                for event in history:
+                    if (event['action'] == '_datachange_') and \
+                       (fieldName in event['changes']): return True
+
     def getHistory(self, startNumber=0, reverse=True, includeInvisible=False,
                    batchSize=5):
         '''Returns the history for this object, sorted in reverse order (most
diff --git a/gen/po.py b/gen/po.py
index 4a89105..411c0a8 100644
--- a/gen/po.py
+++ b/gen/po.py
@@ -198,6 +198,8 @@ appyLabels = [
  ('del_next_events', 'Also delete successive events of the same type.'),
  ('history_insert', 'Inserted by ${userName}'),
  ('history_delete', 'Deleted by ${userName}'),
+ ('changes_show', 'Show changes'),
+ ('changes_hide', 'Hide changes'),
 ]
 
 # Some default values for labels whose ids are not fixed (so they can't be
diff --git a/gen/ui/appy.js b/gen/ui/appy.js
index 07a26db..aa9d8a6 100644
--- a/gen/ui/appy.js
+++ b/gen/ui/appy.js
@@ -192,6 +192,14 @@ function askComputedField(hookId, objectUrl, fieldName) {
   askAjaxChunk(hookId, 'GET', objectUrl, 'widgets/computed', 'viewContent', params);
 }
 
+function askField(hookId, objectUrl, layoutType, showChanges){
+  // Sends an Ajax request for getting the content of any field.
+  var fieldName = hookId.split('_')[1];
+  var params = {'fieldName': fieldName, 'layoutType': layoutType,
+                'showChanges': showChanges};
+  askAjaxChunk(hookId, 'GET', objectUrl, 'widgets/show', 'fieldAjax', params);
+}
+
 // Function used by checkbox widgets for having radio-button-like behaviour
 function toggleCheckbox(visibleCheckbox, hiddenBoolean) {
   vis = document.getElementById(visibleCheckbox);
diff --git a/gen/ui/page.pt b/gen/ui/page.pt
index e49082c..5d27eb0 100644
--- a/gen/ui/page.pt
+++ b/gen/ui/page.pt
@@ -73,7 +73,7 @@
 <metal:history define-macro="objectHistory"
       tal:define="startNumber request/startNumber|python:0;
                   startNumber python: int(startNumber);
-                  batchSize   python: int(request.get('maxPerPage'));
+                  batchSize   python: int(request.get('maxPerPage', 5));
                   historyInfo python: contextObj.getHistory(startNumber, batchSize=batchSize);
                   objs        historyInfo/events;
                   totalNumber historyInfo/totalNumber;
diff --git a/gen/ui/widgets/show.pt b/gen/ui/widgets/show.pt
index 4c35722..dab2906 100644
--- a/gen/ui/widgets/show.pt
+++ b/gen/ui/widgets/show.pt
@@ -5,11 +5,12 @@
     layoutType         The kind of layout: "view"? "edit"? "cell"?
     layout             The layout object that will dictate how object content
                        will be rendered.
+    tagId              The ID of the main tag for this layout.
+
   Options:
     contextMacro       The base folder containing the macros to call for
                        rendering the elements within the layout.
                        Defaults to app.ui
-    tagId              The ID of the main tag for this layout.
     tagName            The name of the main tag for this layout (used
                        a.o. for master/slave relationships).
     tagCss             Some additional CSS class for the main tag
@@ -59,15 +60,19 @@
   Optionally:
     widgetName         If the field to show is within a List, we cheat and
                        include, within the widgetName, the row index.
+    showChanges        Do we need to show a variant of the field showing
+                       successive changes made to it?
+
 </tal:comment>
 <metal:field define-macro="field"
   tal:define="contextMacro python: app.ui.widgets;
+              showChanges  showChanges| python:False;
               layout       python: widget['layouts'][layoutType];
               name         widgetName| widget/name;
               sync         python: widget['sync'][layoutType];
               outerValue   value|nothing;
               rawValue     python: contextObj.getFieldValue(name,onlyIfSync=True,layoutType=layoutType,outerValue=outerValue);
-              value        python: contextObj.getFormattedFieldValue(name, rawValue);
+              value        python: contextObj.getFormattedFieldValue(name, rawValue, showChanges);
               requestValue python: contextObj.getRequestFieldValue(name);
               inRequest    python: request.has_key(name);
               errors       errors | python: ();
@@ -78,10 +83,20 @@
               tagCss       tagCss | python:'';
               tagCss       python: ('%s %s' % (slaveCss, tagCss)).strip();
               tagId        python: '%s_%s' % (contextObj.UID(), name);
-              tagName      python: widget['master'] and 'slave' or ''">
+              tagName      python: widget['master'] and 'slave' or '';">
   <metal:layout use-macro="context/ui/widgets/show/macros/layout"/>
 </metal:field>
 
+<tal:comment replace="nothing">Call the previous macro, but from Ajax.</tal:comment>
+<metal:afield define-macro="fieldAjax"
+             tal:define="widgetName request/fieldName;
+                         layoutType request/layoutType;
+                         showChanges python: request.get('showChanges', 'False') == 'True';
+                         widget python: contextObj.getAppyType(widgetName, asDict=True);
+                         page widget/pageName">
+ <metal:field use-macro="context/ui/widgets/show/macros/field"/>
+</metal:afield>
+
 <tal:comment replace="nothing">
   This macro displays the widget corresponding to a group of widgets.
   It requires:
@@ -223,4 +238,4 @@
 <tal:required metal:define-macro="required"><img tal:attributes="src string: $appUrl/ui/required.gif"/></tal:required>
 
 <tal:comment replace="nothing">Button for showing changes to the field.</tal:comment>
-<tal:changes metal:define-macro="changes"><img tal:attributes="src string: $appUrl/ui/changes.png"/></tal:changes>
+<tal:changes metal:define-macro="changes" tal:condition="python: contextObj.hasHistory(name)"><img style="cursor:pointer" tal:condition="not: showChanges" tal:attributes="src string: $appUrl/ui/changes.png; onclick python: 'askField(\'%s\',\'%s\',\'view\',\'True\')' % (tagId, contextObj.absolute_url()); title python: _('changes_show')"/><img style="cursor:pointer" tal:condition="showChanges" tal:attributes="src string: $appUrl/ui/changesNo.png; onclick python: 'askField(\'%s\',\'%s\',\'view\',\'False\')' % (tagId, contextObj.absolute_url()); title python: _('changes_hide')"/></tal:changes>