diff --git a/common/lib/xmodule/xmodule/abtest_module.py b/common/lib/xmodule/xmodule/abtest_module.py
index e18586726c..0e1c66df8e 100644
--- a/common/lib/xmodule/xmodule/abtest_module.py
+++ b/common/lib/xmodule/xmodule/abtest_module.py
@@ -31,17 +31,19 @@ def group_from_value(groups, v):
     return g
 
 
-class ABTestModule(XModule):
-    """
-    Implements an A/B test with an aribtrary number of competing groups
-    """
-
+class ABTestFields(object):
     group_portions = Object(help="What proportions of students should go in each group", default={DEFAULT: 1}, scope=Scope.content)
     group_assignments = Object(help="What group this user belongs to", scope=Scope.student_preferences, default={})
     group_content = Object(help="What content to display to each group", scope=Scope.content, default={DEFAULT: []})
     experiment = String(help="Experiment that this A/B test belongs to", scope=Scope.content)
     has_children = True
 
+
+class ABTestModule(ABTestFields, XModule):
+    """
+    Implements an A/B test with an aribtrary number of competing groups
+    """
+
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
 
@@ -75,16 +77,11 @@ class ABTestModule(XModule):
 
 # TODO (cpennington): Use Groups should be a first class object, rather than being
 # managed by ABTests
-class ABTestDescriptor(RawDescriptor, XmlDescriptor):
+class ABTestDescriptor(ABTestFields, RawDescriptor, XmlDescriptor):
     module_class = ABTestModule
 
     template_dir_name = "abtest"
 
-    experiment = String(help="Experiment that this A/B test belongs to", scope=Scope.content)
-    group_portions = Object(help="What proportions of students should go in each group", default={})
-    group_content = Object(help="What content to display to each group", scope=Scope.content, default={DEFAULT: []})
-    has_children = True
-
     @classmethod
     def definition_from_xml(cls, xml_object, system):
         """
diff --git a/common/lib/xmodule/xmodule/annotatable_module.py b/common/lib/xmodule/xmodule/annotatable_module.py
index ceeef6d004..5b167dd0be 100644
--- a/common/lib/xmodule/xmodule/annotatable_module.py
+++ b/common/lib/xmodule/xmodule/annotatable_module.py
@@ -12,7 +12,12 @@ from xblock.core import Scope, String
 
 log = logging.getLogger(__name__)
 
-class AnnotatableModule(XModule):
+
+class AnnotatableFields(object):
+    data = String(help="XML data for the annotation", scope=Scope.content)
+
+
+class AnnotatableModule(AnnotatableFields, XModule):
     js = {'coffee': [resource_string(__name__, 'js/src/javascript_loader.coffee'),
                      resource_string(__name__, 'js/src/collapsible.coffee'),
                      resource_string(__name__, 'js/src/html/display.coffee'),
@@ -23,7 +28,6 @@ class AnnotatableModule(XModule):
     css = {'scss': [resource_string(__name__, 'css/annotatable/display.scss')]}
     icon_class = 'annotatable'
 
-    data = String(help="XML data for the annotation", scope=Scope.content)
 
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
@@ -125,7 +129,7 @@ class AnnotatableModule(XModule):
         return self.system.render_template('annotatable.html', context)
 
 
-class AnnotatableDescriptor(RawDescriptor):
+class AnnotatableDescriptor(AnnotatableFields, RawDescriptor):
     module_class = AnnotatableModule
     stores_state = True
     template_dir_name = "annotatable"
diff --git a/common/lib/xmodule/xmodule/capa_module.py b/common/lib/xmodule/xmodule/capa_module.py
index 5f5ae05c7a..9c38347900 100644
--- a/common/lib/xmodule/xmodule/capa_module.py
+++ b/common/lib/xmodule/xmodule/capa_module.py
@@ -83,13 +83,7 @@ class ComplexEncoder(json.JSONEncoder):
         return json.JSONEncoder.default(self, obj)
 
 
-class CapaModule(XModule):
-    '''
-    An XModule implementing LonCapa format problems, implemented by way of
-    capa.capa_problem.LoncapaProblem
-    '''
-    icon_class = 'problem'
-
+class CapaFields(object):
     attempts = StringyInteger(help="Number of attempts taken by the student on this problem", default=0, scope=Scope.student_state)
     max_attempts = StringyInteger(help="Maximum number of attempts that a student is allowed", scope=Scope.settings)
     due = String(help="Date that this problem is due by", scope=Scope.settings)
@@ -103,6 +97,17 @@ class CapaModule(XModule):
     done = Boolean(help="Whether the student has answered the problem", scope=Scope.student_state)
     display_name = String(help="Display name for this module", scope=Scope.settings)
     seed = StringyInteger(help="Random seed for this student", scope=Scope.student_state)
+    weight = StringyFloat(help="How much to weight this problem by", scope=Scope.settings)
+    markdown = String(help="Markdown source of this module", scope=Scope.settings)
+
+
+class CapaModule(CapaFields, XModule):
+    '''
+    An XModule implementing LonCapa format problems, implemented by way of
+    capa.capa_problem.LoncapaProblem
+    '''
+    icon_class = 'problem'
+
 
     js = {'coffee': [resource_string(__name__, 'js/src/capa/display.coffee'),
                      resource_string(__name__, 'js/src/collapsible.coffee'),
@@ -792,7 +797,7 @@ class CapaModule(XModule):
                 'html': self.get_problem_html(encapsulate=False)}
 
 
-class CapaDescriptor(RawDescriptor):
+class CapaDescriptor(CapaFields, RawDescriptor):
     """
     Module implementing problems in the LON-CAPA format,
     as implemented by capa.capa_problem
@@ -800,9 +805,6 @@ class CapaDescriptor(RawDescriptor):
 
     module_class = CapaModule
 
-    weight = StringyFloat(help="How much to weight this problem by", scope=Scope.settings)
-    markdown = String(help="Markdown source of this module", scope=Scope.settings)
-
     stores_state = True
     has_score = True
     template_dir_name = 'problem'
diff --git a/common/lib/xmodule/xmodule/combined_open_ended_module.py b/common/lib/xmodule/xmodule/combined_open_ended_module.py
index 33483037db..fd527f88d7 100644
--- a/common/lib/xmodule/xmodule/combined_open_ended_module.py
+++ b/common/lib/xmodule/xmodule/combined_open_ended_module.py
@@ -27,7 +27,26 @@ VERSION_TUPLES = (
 DEFAULT_VERSION = 1
 DEFAULT_VERSION = str(DEFAULT_VERSION)
 
-class CombinedOpenEndedModule(XModule):
+
+class CombinedOpenEndedFields(object):
+    display_name = String(help="Display name for this module", default="Open Ended Grading", scope=Scope.settings)
+    current_task_number = Integer(help="Current task that the student is on.", default=0, scope=Scope.student_state)
+    task_states = List(help="List of state dictionaries of each task within this module.", scope=Scope.student_state)
+    state = String(help="Which step within the current task that the student is on.", default="initial", scope=Scope.student_state)
+    student_attempts = Integer(help="Number of attempts taken by the student on this problem", default=0, scope=Scope.student_state)
+    ready_to_reset = Boolean(help="If the problem is ready to be reset or not.",  default=False, scope=Scope.student_state)
+    attempts = Integer(help="Maximum number of attempts that a student is allowed.", default=1, scope=Scope.settings)
+    is_graded = Boolean(help="Whether or not the problem is graded.",  default=False, scope=Scope.settings)
+    accept_file_upload = Boolean(help="Whether or not the problem accepts file uploads.",  default=False, scope=Scope.settings)
+    skip_spelling_checks = Boolean(help="Whether or not to skip initial spelling checks.",  default=True, scope=Scope.settings)
+    due = String(help="Date that this problem is due by", default=None, scope=Scope.settings)
+    graceperiod = String(help="Amount of time after the due date that submissions will be accepted", default=None, scope=Scope.settings)
+    max_score = Integer(help="Maximum score for the problem.", default=1, scope=Scope.settings)
+    version = Integer(help="Current version number", default=DEFAULT_VERSION, scope=Scope.settings)
+    data = String(help="XML data for the problem", scope=Scope.content)
+
+
+class CombinedOpenEndedModule(CombinedOpenEndedFields, XModule):
     """
     This is a module that encapsulates all open ended grading (self assessment, peer assessment, etc).
     It transitions between problems, and support arbitrary ordering.
@@ -60,22 +79,6 @@ class CombinedOpenEndedModule(XModule):
 
     icon_class = 'problem'
 
-    display_name = String(help="Display name for this module", default="Open Ended Grading", scope=Scope.settings)
-    current_task_number = Integer(help="Current task that the student is on.", default=0, scope=Scope.student_state)
-    task_states = List(help="List of state dictionaries of each task within this module.", scope=Scope.student_state)
-    state = String(help="Which step within the current task that the student is on.", default="initial", scope=Scope.student_state)
-    student_attempts = Integer(help="Number of attempts taken by the student on this problem", default=0, scope=Scope.student_state)
-    ready_to_reset = Boolean(help="If the problem is ready to be reset or not.",  default=False, scope=Scope.student_state)
-    attempts = Integer(help="Maximum number of attempts that a student is allowed.", default=1, scope=Scope.settings)
-    is_graded = Boolean(help="Whether or not the problem is graded.",  default=False, scope=Scope.settings)
-    accept_file_upload = Boolean(help="Whether or not the problem accepts file uploads.",  default=False, scope=Scope.settings)
-    skip_spelling_checks = Boolean(help="Whether or not to skip initial spelling checks.",  default=True, scope=Scope.settings)
-    due = String(help="Date that this problem is due by", default= None, scope=Scope.settings)
-    graceperiod = String(help="Amount of time after the due date that submissions will be accepted", default=None, scope=Scope.settings)
-    max_score = Integer(help="Maximum score for the problem.", default=1, scope=Scope.settings)
-    version = Integer(help="Current version number", default=DEFAULT_VERSION, scope=Scope.settings)
-    data = String(help="XML data for the problem", scope=Scope.content)
-
     js = {'coffee': [resource_string(__name__, 'js/src/combinedopenended/display.coffee'),
                      resource_string(__name__, 'js/src/collapsible.coffee'),
                      resource_string(__name__, 'js/src/javascript_loader.coffee'),
@@ -192,7 +195,7 @@ class CombinedOpenEndedModule(XModule):
                 setattr(self,attribute, getattr(self.child_module,attribute))
 
 
-class CombinedOpenEndedDescriptor(RawDescriptor):
+class CombinedOpenEndedDescriptor(CombinedOpenEndedFields, RawDescriptor):
     """
     Module for adding combined open ended questions
     """
diff --git a/common/lib/xmodule/xmodule/conditional_module.py b/common/lib/xmodule/xmodule/conditional_module.py
index 8e1290400f..a9375cae78 100644
--- a/common/lib/xmodule/xmodule/conditional_module.py
+++ b/common/lib/xmodule/xmodule/conditional_module.py
@@ -17,7 +17,11 @@ from xmodule.modulestore.exceptions import ItemNotFoundError
 log = logging.getLogger('mitx.' + __name__)
 
 
-class ConditionalModule(XModule):
+class ConditionalFields(object):
+    show_tag_list = List(help="Poll answers", scope=Scope.content)
+
+
+class ConditionalModule(ConditionalFields, XModule):
     """
     Blocks child module from showing unless certain conditions are met.
 
@@ -134,7 +138,7 @@ class ConditionalModule(XModule):
         return new_class
 
 
-class ConditionalDescriptor(SequenceDescriptor):
+class ConditionalDescriptor(ConditionalFields, SequenceDescriptor):
     """Descriptor for conditional xmodule."""
     _tag_name = 'conditional'
 
@@ -145,7 +149,6 @@ class ConditionalDescriptor(SequenceDescriptor):
     stores_state = True
     has_score = False
 
-    show_tag_list = List(help="Poll answers", scope=Scope.content)
 
     @staticmethod
     def parse_sources(xml_element, system, return_descriptor=False):
diff --git a/common/lib/xmodule/xmodule/course_module.py b/common/lib/xmodule/xmodule/course_module.py
index 9c757d0ac6..7c47e0887a 100644
--- a/common/lib/xmodule/xmodule/course_module.py
+++ b/common/lib/xmodule/xmodule/course_module.py
@@ -147,9 +147,7 @@ class TextbookList(List):
         return json_data
 
 
-class CourseDescriptor(SequenceDescriptor):
-    module_class = SequenceModule
-
+class CourseFields(object):
     textbooks = TextbookList(help="List of pairs of (title, url) for textbooks used in this course", scope=Scope.content)
     wiki_slug = String(help="Slug that points to the wiki for this course", scope=Scope.content)
     enrollment_start = Date(help="Date that enrollment for this class is opened", scope=Scope.settings)
@@ -207,6 +205,10 @@ class CourseDescriptor(SequenceDescriptor):
     # Explicit comparison to True because we always want to return a bool.
     hide_progress_tab = Boolean(help="DO NOT USE THIS", scope=Scope.settings)
 
+
+class CourseDescriptor(CourseFields, SequenceDescriptor):
+    module_class = SequenceModule
+
     template_dir_name = 'course'
 
 
diff --git a/common/lib/xmodule/xmodule/discussion_module.py b/common/lib/xmodule/xmodule/discussion_module.py
index 86325a19e8..7725a88e77 100644
--- a/common/lib/xmodule/xmodule/discussion_module.py
+++ b/common/lib/xmodule/xmodule/discussion_module.py
@@ -6,17 +6,20 @@ from xmodule.raw_module import RawDescriptor
 from xblock.core import String, Scope
 
 
-class DiscussionModule(XModule):
+class DiscussionFields(object):
+    discussion_id = String(scope=Scope.settings)
+    discussion_category = String(scope=Scope.settings)
+    discussion_target = String(scope=Scope.settings)
+    sort_key = String(scope=Scope.settings)
+
+
+class DiscussionModule(DiscussionFields, XModule):
     js = {'coffee':
             [resource_string(__name__, 'js/src/time.coffee'),
             resource_string(__name__, 'js/src/discussion/display.coffee')]
         }
     js_module_name = "InlineDiscussion"
 
-    discussion_id = String(scope=Scope.settings)
-    discussion_category = String(scope=Scope.settings)
-    discussion_target = String(scope=Scope.settings)
-    sort_key = String(scope=Scope.settings)
 
     def get_html(self):
         context = {
@@ -25,7 +28,7 @@ class DiscussionModule(XModule):
         return self.system.render_template('discussion/_discussion_module.html', context)
 
 
-class DiscussionDescriptor(RawDescriptor):
+class DiscussionDescriptor(DiscussionFields, RawDescriptor):
     module_class = DiscussionModule
     template_dir_name = "discussion"
 
@@ -35,8 +38,3 @@ class DiscussionDescriptor(RawDescriptor):
     metadata_translations = dict(RawDescriptor.metadata_translations)
     metadata_translations['id'] = 'discussion_id'
     metadata_translations['for'] = 'discussion_target'
-
-    discussion_id = String(scope=Scope.settings)
-    discussion_category = String(scope=Scope.settings)
-    discussion_target = String(scope=Scope.settings)
-    sort_key = String(scope=Scope.settings)
diff --git a/common/lib/xmodule/xmodule/editing_module.py b/common/lib/xmodule/xmodule/editing_module.py
index 9ff0124dc6..b93727a96b 100644
--- a/common/lib/xmodule/xmodule/editing_module.py
+++ b/common/lib/xmodule/xmodule/editing_module.py
@@ -6,7 +6,11 @@ import logging
 log = logging.getLogger(__name__)
 
 
-class EditingDescriptor(MakoModuleDescriptor):
+class EditingFields(object):
+    data = String(scope=Scope.content, default='')
+
+
+class EditingDescriptor(EditingFields, MakoModuleDescriptor):
     """
     Module that provides a raw editing view of its data and children.  It does not
     perform any validation on its definition---just passes it along to the browser.
@@ -15,8 +19,6 @@ class EditingDescriptor(MakoModuleDescriptor):
     """
     mako_template = "widgets/raw-edit.html"
 
-    data = String(scope=Scope.content, default='')
-
     # cdodge: a little refactoring here, since we're basically doing the same thing
     # here as with our parent class, let's call into it to get the basic fields
     # set and then add our additional fields. Trying to keep it DRY.
diff --git a/common/lib/xmodule/xmodule/error_module.py b/common/lib/xmodule/xmodule/error_module.py
index 3ed53cae91..d2135302da 100644
--- a/common/lib/xmodule/xmodule/error_module.py
+++ b/common/lib/xmodule/xmodule/error_module.py
@@ -21,10 +21,13 @@ log = logging.getLogger(__name__)
 # decides whether to create a staff or not-staff module.
 
 
-class ErrorModule(XModule):
-
+class ErrorFields(object):
     contents = String(scope=Scope.content)
     error_msg = String(scope=Scope.content)
+    display_name = String(scope=Scope.settings)
+
+
+class ErrorModule(ErrorFields, XModule):
 
     def get_html(self):
         '''Show an error to staff.
@@ -38,7 +41,7 @@ class ErrorModule(XModule):
             })
 
 
-class NonStaffErrorModule(XModule):
+class NonStaffErrorModule(ErrorFields, XModule):
     def get_html(self):
         '''Show an error to a student.
         TODO (vshnayder): proper style, divs, etc.
@@ -51,16 +54,12 @@ class NonStaffErrorModule(XModule):
             })
 
 
-class ErrorDescriptor(JSONEditingDescriptor):
+class ErrorDescriptor(ErrorFields, JSONEditingDescriptor):
     """
     Module that provides a raw editing view of broken xml.
     """
     module_class = ErrorModule
 
-    contents = String(scope=Scope.content)
-    error_msg = String(scope=Scope.content)
-    display_name = String(scope=Scope.settings)
-
     @classmethod
     def _construct(self, system, contents, error_msg, location):
 
diff --git a/common/lib/xmodule/xmodule/foldit_module.py b/common/lib/xmodule/xmodule/foldit_module.py
index 3bec3107ff..d8111eecac 100644
--- a/common/lib/xmodule/xmodule/foldit_module.py
+++ b/common/lib/xmodule/xmodule/foldit_module.py
@@ -11,10 +11,8 @@ from xblock.core import Scope, Integer, String
 
 log = logging.getLogger(__name__)
 
-class FolditModule(XModule):
-
-    css = {'scss': [resource_string(__name__, 'css/foldit/leaderboard.scss')]}
 
+class FolditFields(object):
     # default to what Spring_7012x uses
     required_level = Integer(default=4, scope=Scope.settings)
     required_sublevel = Integer(default=5, scope=Scope.settings)
@@ -23,6 +21,11 @@ class FolditModule(XModule):
     show_basic_score = String(scope=Scope.settings, default='false')
     show_leaderboard = String(scope=Scope.settings, default='false')
 
+
+class FolditModule(FolditFields, XModule):
+
+    css = {'scss': [resource_string(__name__, 'css/foldit/leaderboard.scss')]}
+
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
         """
@@ -154,7 +157,7 @@ class FolditModule(XModule):
 
 
 
-class FolditDescriptor(XmlDescriptor, EditingDescriptor):
+class FolditDescriptor(FolditFields, XmlDescriptor, EditingDescriptor):
     """
     Module for adding Foldit problems to courses
     """
diff --git a/common/lib/xmodule/xmodule/gst_module.py b/common/lib/xmodule/xmodule/gst_module.py
index ebbab0ec5a..00e8cf1f10 100644
--- a/common/lib/xmodule/xmodule/gst_module.py
+++ b/common/lib/xmodule/xmodule/gst_module.py
@@ -20,7 +20,12 @@ from xblock.core import String, Scope
 log = logging.getLogger(__name__)
 
 
-class GraphicalSliderToolModule(XModule):
+class GraphicalSliderToolFields(object):
+    render = String(scope=Scope.content)
+    configuration = String(scope=Scope.content)
+
+
+class GraphicalSliderToolModule(GraphicalSliderToolFields, XModule):
     ''' Graphical-Slider-Tool Module
     '''
 
@@ -44,9 +49,6 @@ class GraphicalSliderToolModule(XModule):
     }
     js_module_name = "GraphicalSliderTool"
 
-    render = String(scope=Scope.content)
-    configuration = String(scope=Scope.content)
-
     def get_html(self):
         """ Renders parameters to template. """
 
@@ -137,13 +139,10 @@ class GraphicalSliderToolModule(XModule):
                 '">' + self.configuration + '</root>'))
 
 
-class GraphicalSliderToolDescriptor(MakoModuleDescriptor, XmlDescriptor):
+class GraphicalSliderToolDescriptor(GraphicalSliderToolFields, MakoModuleDescriptor, XmlDescriptor):
     module_class = GraphicalSliderToolModule
     template_dir_name = 'graphical_slider_tool'
 
-    render = String(scope=Scope.content)
-    configuration = String(scope=Scope.content)
-
     @classmethod
     def definition_from_xml(cls, xml_object, system):
         """
diff --git a/common/lib/xmodule/xmodule/html_module.py b/common/lib/xmodule/xmodule/html_module.py
index 1f9228b47f..e9cec32e3e 100644
--- a/common/lib/xmodule/xmodule/html_module.py
+++ b/common/lib/xmodule/xmodule/html_module.py
@@ -17,7 +17,11 @@ from xmodule.xml_module import XmlDescriptor, name_to_pathname
 log = logging.getLogger("mitx.courseware")
 
 
-class HtmlModule(XModule):
+class HtmlFields(object):
+    data = String(help="Html contents to display for this module", scope=Scope.content)
+
+
+class HtmlModule(HtmlFields, XModule):
     js = {'coffee': [resource_string(__name__, 'js/src/javascript_loader.coffee'),
                      resource_string(__name__, 'js/src/collapsible.coffee'),
                      resource_string(__name__, 'js/src/html/display.coffee')
@@ -26,13 +30,11 @@ class HtmlModule(XModule):
     js_module_name = "HTMLModule"
     css = {'scss': [resource_string(__name__, 'css/html/display.scss')]}
 
-    data = String(help="Html contents to display for this module", scope=Scope.content)
-
     def get_html(self):
         return self.data
 
 
-class HtmlDescriptor(XmlDescriptor, EditingDescriptor):
+class HtmlDescriptor(HtmlFields, XmlDescriptor, EditingDescriptor):
     """
     Module for putting raw html in a course
     """
@@ -41,8 +43,6 @@ class HtmlDescriptor(XmlDescriptor, EditingDescriptor):
     filename_extension = "xml"
     template_dir_name = "html"
 
-    data = String(help="Html contents to display for this module", scope=Scope.content)
-
     js = {'coffee': [resource_string(__name__, 'js/src/html/edit.coffee')]}
     js_module_name = "HTMLEditingDescriptor"
     css = {'scss': [resource_string(__name__, 'css/editor/edit.scss'), resource_string(__name__, 'css/html/edit.scss')]}
diff --git a/common/lib/xmodule/xmodule/modulestore/mongo.py b/common/lib/xmodule/xmodule/modulestore/mongo.py
index 4377c34361..c1a069ab12 100644
--- a/common/lib/xmodule/xmodule/modulestore/mongo.py
+++ b/common/lib/xmodule/xmodule/modulestore/mongo.py
@@ -95,7 +95,7 @@ class MongoKeyValueStore(KeyValueStore):
             else:
                 return key.field_name in self._data
         else:
-            raise InvalidScopeError(key.scope)
+            return False
 
 MongoUsage = namedtuple('MongoUsage', 'id, def_id')
 
diff --git a/common/lib/xmodule/xmodule/open_ended_grading_classes/self_assessment_module.py b/common/lib/xmodule/xmodule/open_ended_grading_classes/self_assessment_module.py
index 688013063e..709cd98263 100644
--- a/common/lib/xmodule/xmodule/open_ended_grading_classes/self_assessment_module.py
+++ b/common/lib/xmodule/xmodule/open_ended_grading_classes/self_assessment_module.py
@@ -5,7 +5,6 @@ from lxml import etree
 from xmodule.capa_module import ComplexEncoder
 from xmodule.progress import Progress
 from xmodule.stringify import stringify_children
-from xblock.core import List, Integer, String, Scope
 import openendedchild
 
 from combined_open_ended_rubric import CombinedOpenEndedRubric
diff --git a/common/lib/xmodule/xmodule/peer_grading_module.py b/common/lib/xmodule/xmodule/peer_grading_module.py
index 5444981e2b..347a121614 100644
--- a/common/lib/xmodule/xmodule/peer_grading_module.py
+++ b/common/lib/xmodule/xmodule/peer_grading_module.py
@@ -27,7 +27,17 @@ IS_GRADED = True
 EXTERNAL_GRADER_NO_CONTACT_ERROR = "Failed to contact external graders.  Please notify course staff."
 
 
-class PeerGradingModule(XModule):
+class PeerGradingFields(object):
+    use_for_single_location = Boolean(help="Whether to use this for a single location or as a panel.", default=USE_FOR_SINGLE_LOCATION, scope=Scope.settings)
+    link_to_location = String(help="The location this problem is linked to.", default=LINK_TO_LOCATION, scope=Scope.settings)
+    is_graded = Boolean(help="Whether or not this module is scored.",default=IS_GRADED, scope=Scope.settings)
+    display_due_date_string = String(help="Due date that should be displayed.", default=None, scope=Scope.settings)
+    grace_period_string = String(help="Amount of grace to give on the due date.", default=None, scope=Scope.settings)
+    max_grade = Integer(help="The maximum grade that a student can receieve for this problem.", default=MAX_SCORE, scope=Scope.settings)
+    student_data_for_location = Object(help="Student data for a given peer grading problem.", default=json.dumps({}),scope=Scope.student_state)
+
+
+class PeerGradingModule(PeerGradingFields, XModule):
     _VERSION = 1
 
     js = {'coffee': [resource_string(__name__, 'js/src/peergrading/peer_grading.coffee'),
@@ -39,14 +49,6 @@ class PeerGradingModule(XModule):
 
     css = {'scss': [resource_string(__name__, 'css/combinedopenended/display.scss')]}
 
-    use_for_single_location = Boolean(help="Whether to use this for a single location or as a panel.", default=USE_FOR_SINGLE_LOCATION, scope=Scope.settings)
-    link_to_location = String(help="The location this problem is linked to.", default=LINK_TO_LOCATION, scope=Scope.settings)
-    is_graded = Boolean(help="Whether or not this module is scored.",default=IS_GRADED, scope=Scope.settings)
-    display_due_date_string = String(help="Due date that should be displayed.", default=None, scope=Scope.settings)
-    grace_period_string = String(help="Amount of grace to give on the due date.", default=None, scope=Scope.settings)
-    max_grade = Integer(help="The maximum grade that a student can receieve for this problem.", default=MAX_SCORE, scope=Scope.settings)
-    student_data_for_location = Object(help="Student data for a given peer grading problem.", default=json.dumps({}),scope=Scope.student_state)
-
     def __init__(self, system, location, descriptor, model_data):
         XModule.__init__(self, system, location, descriptor, model_data)
 
@@ -556,7 +558,7 @@ class PeerGradingModule(XModule):
         return json.dumps(state)
 
 
-class PeerGradingDescriptor(RawDescriptor):
+class PeerGradingDescriptor(PeerGradingFields, RawDescriptor):
     """
     Module for adding peer grading questions
     """
diff --git a/common/lib/xmodule/xmodule/poll_module.py b/common/lib/xmodule/xmodule/poll_module.py
index 321929030c..d5dabecdca 100644
--- a/common/lib/xmodule/xmodule/poll_module.py
+++ b/common/lib/xmodule/xmodule/poll_module.py
@@ -26,17 +26,7 @@ from xblock.core import Scope, String, Object, Boolean, List
 log = logging.getLogger(__name__)
 
 
-class PollModule(XModule):
-    """Poll Module"""
-    js = {
-      'coffee': [resource_string(__name__, 'js/src/javascript_loader.coffee')],
-      'js': [resource_string(__name__, 'js/src/poll/logme.js'),
-             resource_string(__name__, 'js/src/poll/poll.js'),
-             resource_string(__name__, 'js/src/poll/poll_main.js')]
-         }
-    css = {'scss': [resource_string(__name__, 'css/poll/display.scss')]}
-    js_module_name = "Poll"
-
+class PollFields(object):
     # Name of poll to use in links to this poll
     display_name = String(help="Display name for this module", scope=Scope.settings)
 
@@ -47,6 +37,20 @@ class PollModule(XModule):
     answers = List(help="Poll answers from xml", scope=Scope.content, default=[])
     question = String(help="Poll question", scope=Scope.content, default='')
 
+    id = String(help="ID attribute for this module", scope=Scope.settings)
+
+
+class PollModule(PollFields, XModule):
+    """Poll Module"""
+    js = {
+      'coffee': [resource_string(__name__, 'js/src/javascript_loader.coffee')],
+      'js': [resource_string(__name__, 'js/src/poll/logme.js'),
+             resource_string(__name__, 'js/src/poll/poll.js'),
+             resource_string(__name__, 'js/src/poll/poll_main.js')]
+         }
+    css = {'scss': [resource_string(__name__, 'css/poll/display.scss')]}
+    js_module_name = "Poll"
+
     def handle_ajax(self, dispatch, get):
         """Ajax handler.
 
@@ -135,7 +139,7 @@ class PollModule(XModule):
             'reset': str(self.descriptor.xml_attributes.get('reset', 'true')).lower()})
 
 
-class PollDescriptor(MakoModuleDescriptor, XmlDescriptor):
+class PollDescriptor(PollFields, MakoModuleDescriptor, XmlDescriptor):
     _tag_name = 'poll_question'
     _child_tag_name = 'answer'
 
@@ -143,11 +147,6 @@ class PollDescriptor(MakoModuleDescriptor, XmlDescriptor):
     template_dir_name = 'poll'
     stores_state = True
 
-    answers = List(help="Poll answers", scope=Scope.content, default=[])
-    question = String(help="Poll question", scope=Scope.content, default='')
-    display_name = String(help="Display name for this module", scope=Scope.settings)
-    id = String(help="ID attribute for this module", scope=Scope.settings)
-
     @classmethod
     def definition_from_xml(cls, xml_object, system):
         """Pull out the data into dictionary.
diff --git a/common/lib/xmodule/xmodule/randomize_module.py b/common/lib/xmodule/xmodule/randomize_module.py
index aa926b836d..6620ab3cf7 100644
--- a/common/lib/xmodule/xmodule/randomize_module.py
+++ b/common/lib/xmodule/xmodule/randomize_module.py
@@ -9,7 +9,11 @@ from xblock.core import Scope, Integer
 log = logging.getLogger('mitx.' + __name__)
 
 
-class RandomizeModule(XModule):
+class RandomizeFields(object):
+    choice = Integer(help="Which random child was chosen", scope=Scope.student_state)
+
+
+class RandomizeModule(RandomizeFields, XModule):
     """
     Chooses a random child module.  Chooses the same one every time for each student.
 
@@ -31,9 +35,6 @@ class RandomizeModule(XModule):
         grading interaction is a tangle between super and subclasses of descriptors and
         modules.
 """
-
-    choice = Integer(help="Which random child was chosen", scope=Scope.student_state)
-
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
 
@@ -64,7 +65,6 @@ class RandomizeModule(XModule):
             self.child_descriptor = None
             self.child = None
 
-
     def get_child_descriptors(self):
         """
         For grading--return just the chosen child.
@@ -86,7 +86,7 @@ class RandomizeModule(XModule):
         return self.child.get_icon_class() if self.child else 'other'
 
 
-class RandomizeDescriptor(SequenceDescriptor):
+class RandomizeDescriptor(RandomizeFields, SequenceDescriptor):
     # the editing interface can be the same as for sequences -- just a container
     module_class = RandomizeModule
 
diff --git a/common/lib/xmodule/xmodule/seq_module.py b/common/lib/xmodule/xmodule/seq_module.py
index c0f85f4cec..f8e982f1a0 100644
--- a/common/lib/xmodule/xmodule/seq_module.py
+++ b/common/lib/xmodule/xmodule/seq_module.py
@@ -18,7 +18,15 @@ log = logging.getLogger(__name__)
 class_priority = ['video', 'problem']
 
 
-class SequenceModule(XModule):
+class SequenceFields(object):
+    has_children = True
+
+    # NOTE: Position is 1-indexed.  This is silly, but there are now student
+    # positions saved on prod, so it's not easy to fix.
+    position = Integer(help="Last tab viewed in this sequence", scope=Scope.student_state)
+
+
+class SequenceModule(SequenceFields, XModule):
     ''' Layout module which lays out content in a temporal sequence
     '''
     js = {'coffee': [resource_string(__name__,
@@ -27,11 +35,6 @@ class SequenceModule(XModule):
     css = {'scss': [resource_string(__name__, 'css/sequence/display.scss')]}
     js_module_name = "Sequence"
 
-    has_children = True
-
-    # NOTE: Position is 1-indexed.  This is silly, but there are now student
-    # positions saved on prod, so it's not easy to fix.
-    position = Integer(help="Last tab viewed in this sequence", scope=Scope.student_state)
 
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
@@ -114,11 +117,10 @@ class SequenceModule(XModule):
         return new_class
 
 
-class SequenceDescriptor(MakoModuleDescriptor, XmlDescriptor):
+class SequenceDescriptor(SequenceFields, MakoModuleDescriptor, XmlDescriptor):
     mako_template = 'widgets/sequence-edit.html'
     module_class = SequenceModule
 
-    has_children = True
     stores_state = True  # For remembering where in the sequence the student is
 
     js = {'coffee': [resource_string(__name__, 'js/src/sequence/edit.coffee')]}
diff --git a/common/lib/xmodule/xmodule/timelimit_module.py b/common/lib/xmodule/xmodule/timelimit_module.py
index d327342d34..efa47a5dca 100644
--- a/common/lib/xmodule/xmodule/timelimit_module.py
+++ b/common/lib/xmodule/xmodule/timelimit_module.py
@@ -15,11 +15,7 @@ from xblock.core import Float, String, Boolean, Scope
 log = logging.getLogger(__name__)
 
 
-class TimeLimitModule(XModule):
-    '''
-    Wrapper module which imposes a time constraint for the completion of its child.
-    '''
-
+class TimeLimitFields(object):
     beginning_at = Float(help="The time this timer was started", scope=Scope.student_state)
     ending_at = Float(help="The time this timer will end", scope=Scope.student_state)
     accomodation_code = String(help="A code indicating accommodations to be given the student", scope=Scope.student_state)
@@ -27,6 +23,12 @@ class TimeLimitModule(XModule):
     duration = Float(help="The length of this timer", scope=Scope.settings)
     suppress_toplevel_navigation = Boolean(help="Whether the toplevel navigation should be suppressed when viewing this module", scope=Scope.settings)
 
+
+class TimeLimitModule(TimeLimitFields, XModule):
+    '''
+    Wrapper module which imposes a time constraint for the completion of its child.
+    '''
+
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
 
@@ -117,7 +119,7 @@ class TimeLimitModule(XModule):
         else:
             return "other"
 
-class TimeLimitDescriptor(XMLEditingDescriptor, XmlDescriptor):
+class TimeLimitDescriptor(TimeLimitFields, XMLEditingDescriptor, XmlDescriptor):
 
     module_class = TimeLimitModule
 
diff --git a/common/lib/xmodule/xmodule/video_module.py b/common/lib/xmodule/xmodule/video_module.py
index 1396885bfb..4fc87b0750 100644
--- a/common/lib/xmodule/xmodule/video_module.py
+++ b/common/lib/xmodule/xmodule/video_module.py
@@ -19,7 +19,13 @@ import time
 log = logging.getLogger(__name__)
 
 
-class VideoModule(XModule):
+class VideoFields(object):
+    data = String(help="XML data for the problem", scope=Scope.content)
+    position = Integer(help="Current position in the video", scope=Scope.student_state, default=0)
+    display_name = String(help="Display name for this module", scope=Scope.settings)
+
+
+class VideoModule(VideoFields, XModule):
     video_time = 0
     icon_class = 'video'
 
@@ -33,10 +39,6 @@ class VideoModule(XModule):
     css = {'scss': [resource_string(__name__, 'css/video/display.scss')]}
     js_module_name = "Video"
 
-    data = String(help="XML data for the problem", scope=Scope.content)
-    position = Integer(help="Current position in the video", scope=Scope.student_state, default=0)
-    display_name = String(help="Display name for this module", scope=Scope.settings)
-
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
 
@@ -151,7 +153,7 @@ class VideoModule(XModule):
         })
 
 
-class VideoDescriptor(RawDescriptor):
+class VideoDescriptor(VideoFields, RawDescriptor):
     module_class = VideoModule
     stores_state = True
     template_dir_name = "video"
diff --git a/common/lib/xmodule/xmodule/videoalpha_module.py b/common/lib/xmodule/xmodule/videoalpha_module.py
index c42c06c6be..5ae8d890e6 100644
--- a/common/lib/xmodule/xmodule/videoalpha_module.py
+++ b/common/lib/xmodule/xmodule/videoalpha_module.py
@@ -19,7 +19,13 @@ import time
 log = logging.getLogger(__name__)
 
 
-class VideoAlphaModule(XModule):
+class VideoAlphaFields(object):
+    data = String(help="XML data for the problem", scope=Scope.content)
+    position = Integer(help="Current position in the video", scope=Scope.student_state, default=0)
+    display_name = String(help="Display name for this module", scope=Scope.settings)
+
+
+class VideoAlphaModule(VideoAlphaFields, XModule):
     """
     XML source example:
 
@@ -47,10 +53,6 @@ class VideoAlphaModule(XModule):
     css = {'scss': [resource_string(__name__, 'css/videoalpha/display.scss')]}
     js_module_name = "VideoAlpha"
 
-    data = String(help="XML data for the problem", scope=Scope.content)
-    position = Integer(help="Current position in the video", scope=Scope.student_state, default=0)
-    display_name = String(help="Display name for this module", scope=Scope.settings)
-
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
         xmltree = etree.fromstring(self.data)
@@ -147,7 +149,7 @@ class VideoAlphaModule(XModule):
         })
 
 
-class VideoAlphaDescriptor(RawDescriptor):
+class VideoAlphaDescriptor(VideoAlphaFields, RawDescriptor):
     module_class = VideoAlphaModule
     stores_state = True
     template_dir_name = "videoalpha"
diff --git a/common/lib/xmodule/xmodule/x_module.py b/common/lib/xmodule/xmodule/x_module.py
index e1327df49a..9b014e10cf 100644
--- a/common/lib/xmodule/xmodule/x_module.py
+++ b/common/lib/xmodule/xmodule/x_module.py
@@ -82,7 +82,15 @@ class HTMLSnippet(object):
                                   .format(self.__class__))
 
 
-class XModule(HTMLSnippet, XBlock):
+class XModuleFields(object):
+    display_name = String(
+        help="Display name for this module",
+        scope=Scope.settings,
+        default=None,
+    )
+
+
+class XModule(XModuleFields, HTMLSnippet, XBlock):
     ''' Implements a generic learning module.
 
         Subclasses must at a minimum provide a definition for get_html in order
@@ -99,11 +107,6 @@ class XModule(HTMLSnippet, XBlock):
     # in the module
     icon_class = 'other'
 
-    display_name = String(
-        help="Display name for this module",
-        scope=Scope.settings,
-        default=None,
-    )
 
     def __init__(self, system, location, descriptor, model_data):
         '''
@@ -307,7 +310,7 @@ class ResourceTemplates(object):
         return templates
 
 
-class XModuleDescriptor(HTMLSnippet, ResourceTemplates, XBlock):
+class XModuleDescriptor(XModuleFields, HTMLSnippet, ResourceTemplates, XBlock):
     """
     An XModuleDescriptor is a specification for an element of a course. This
     could be a problem, an organizational element (a group of content), or a
@@ -352,12 +355,6 @@ class XModuleDescriptor(HTMLSnippet, ResourceTemplates, XBlock):
     FoldIt, which posts grade-changing updates through a separate API.
     """
 
-    display_name = String(
-        help="Display name for this module",
-        scope=Scope.settings,
-        default=None,
-    )
-
     # VS[compat].  Backwards compatibility code that can go away after
     # importing 2012 courses.
     # A set of metadata key conversions that we want to make
diff --git a/local-requirements.txt b/local-requirements.txt
index 512c6b3ff6..bea69ec53a 100644
--- a/local-requirements.txt
+++ b/local-requirements.txt
@@ -6,4 +6,4 @@
 # XBlock:
 # Might change frequently, so put it in local-requirements.txt,
 # but conceptually is an external package, so it is in a separate repo.
--e git+ssh://git@github.com/MITx/xmodule-debugger@6d5c2443#egg=XBlock
+-e git+ssh://git@github.com/MITx/xmodule-debugger@5026e686#egg=XBlock