diff --git a/taglib/mpeg/id3v2/frames/textidentificationframe.cpp b/taglib/mpeg/id3v2/frames/textidentificationframe.cpp
index 6a9d760b..d1336d22 100644
--- a/taglib/mpeg/id3v2/frames/textidentificationframe.cpp
+++ b/taglib/mpeg/id3v2/frames/textidentificationframe.cpp
@@ -25,7 +25,7 @@
 
 #include <tbytevectorlist.h>
 #include <id3v2tag.h>
-
+#include <tdebug.h>
 #include "textidentificationframe.h"
 #include "tpropertymap.h"
 #include "id3v1genres.h"
@@ -321,6 +321,14 @@ UserTextIdentificationFrame::UserTextIdentificationFrame(const ByteVector &data)
   checkFields();
 }
 
+UserTextIdentificationFrame::UserTextIdentificationFrame(const String &description, const StringList &values, String::Type encoding) :
+    TextIdentificationFrame("TXXX", encoding),
+    d(0)
+{
+  setDescription(description);
+  setText(values);
+}
+
 String UserTextIdentificationFrame::toString() const
 {
   return "[" + description() + "] " + fieldList().toString();
@@ -378,10 +386,12 @@ PropertyMap UserTextIdentificationFrame::asProperties() const
   String key = map.prepareKey(tagName);
   if(key.isNull()) // this frame's description is not a valid PropertyMap key -> add to unsupported list
     map.unsupportedData().append(L"TXXX/" + description());
-  else
-    for(StringList::ConstIterator it = fieldList().begin(); it != fieldList().end(); ++it)
+  else {
+    StringList v = fieldList();
+    for(StringList::ConstIterator it = v.begin(); it != v.end(); ++it)
       if(*it != description())
         map.insert(key, *it);
+  }
   return map;
 }
 
diff --git a/taglib/mpeg/id3v2/frames/textidentificationframe.h b/taglib/mpeg/id3v2/frames/textidentificationframe.h
index b82e7d3a..283f0c72 100644
--- a/taglib/mpeg/id3v2/frames/textidentificationframe.h
+++ b/taglib/mpeg/id3v2/frames/textidentificationframe.h
@@ -253,9 +253,9 @@ namespace TagLib {
 
       /*!
        * Creates a user defined text identification frame with the given \a description
-       * and \a text.
+       * and \a values.
        */
-      UserTextIdentificationFrame(const String &description, const StringList &values, String::Type encoding = String::Latin1);
+      UserTextIdentificationFrame(const String &description, const StringList &values, String::Type encoding = String::UTF8);
 
       virtual String toString() const;
 
diff --git a/taglib/mpeg/id3v2/frames/urllinkframe.cpp b/taglib/mpeg/id3v2/frames/urllinkframe.cpp
index db872db2..f06a04dd 100644
--- a/taglib/mpeg/id3v2/frames/urllinkframe.cpp
+++ b/taglib/mpeg/id3v2/frames/urllinkframe.cpp
@@ -26,6 +26,7 @@
  ***************************************************************************/
 
 #include "urllinkframe.h"
+#include "id3v2tag.h"
 #include <tdebug.h>
 #include <tstringlist.h>
 #include <tpropertymap.h>
@@ -167,6 +168,17 @@ PropertyMap UserUrlLinkFrame::asProperties() const
   return map;
 }
 
+UserUrlLinkFrame *UserUrlLinkFrame::find(ID3v2::Tag *tag, const String &description) // static
+{
+  FrameList l = tag->frameList("WXXX");
+  for(FrameList::Iterator it = l.begin(); it != l.end(); ++it) {
+    UserUrlLinkFrame *f = dynamic_cast<UserUrlLinkFrame *>(*it);
+    if(f && f->description() == description)
+      return f;
+  }
+  return 0;
+}
+
 void UserUrlLinkFrame::parseFields(const ByteVector &data)
 {
   if(data.size() < 2) {
diff --git a/taglib/mpeg/id3v2/frames/urllinkframe.h b/taglib/mpeg/id3v2/frames/urllinkframe.h
index 4eea36b3..7ac966b2 100644
--- a/taglib/mpeg/id3v2/frames/urllinkframe.h
+++ b/taglib/mpeg/id3v2/frames/urllinkframe.h
@@ -161,6 +161,12 @@ namespace TagLib {
        */
       PropertyMap asProperties() const;
 
+      /*!
+       * Searches for the user defined url frame with the description \a description
+       * in \a tag.  This returns null if no matching frames were found.
+       */
+      static UserUrlLinkFrame *find(Tag *tag, const String &description);
+
     protected:
       virtual void parseFields(const ByteVector &data);
       virtual ByteVector renderFields() const;
diff --git a/taglib/mpeg/id3v2/id3v2tag.cpp b/taglib/mpeg/id3v2/id3v2tag.cpp
index 05d58f48..e6be1f91 100644
--- a/taglib/mpeg/id3v2/id3v2tag.cpp
+++ b/taglib/mpeg/id3v2/id3v2tag.cpp
@@ -337,11 +337,42 @@ void ID3v2::Tag::removeFrames(const ByteVector &id)
 PropertyMap ID3v2::Tag::properties() const
 {
   PropertyMap properties;
-  for(FrameList::ConstIterator it = frameList().begin(); it != frameList().end(); ++it)
-    properties.merge((*it)->asProperties());
+
+  for(FrameList::ConstIterator it = frameList().begin(); it != frameList().end(); ++it) {
+    PropertyMap props = (*it)->asProperties();
+    debug(props);
+    properties.merge(props);
+  }
   return properties;
 }
 
+void ID3v2::Tag::removeUnsupportedProperties(const StringList &properties)
+{
+  // entries of unsupportedData() are usually frame IDs which are not supported
+  // by the PropertyMap interface. Three special cases exist: TXXX, WXXX, and COMM
+  // frames may also be unsupported if their description() is not a valid key.
+  for(StringList::ConstIterator it = properties.begin(); it != properties.end(); ++it){
+    ByteVector id = it->substr(0,4).data(String::Latin1);
+    if(id == "TXXX") {
+      String description = it->substr(5);
+      Frame *frame = UserTextIdentificationFrame::find(this, description);
+      if(frame)
+        removeFrame(frame);
+    } else if(id == "WXXX") {
+      String description = it->substr(5);
+      Frame *frame = UserUrlLinkFrame::find(this, description);
+      if(frame)
+        removeFrame(frame);
+    } else if(id == "COMM") {
+      String description = it->substr(5);
+      Frame *frame = CommentsFrame::findByDescription(this, description);
+      if(frame)
+        removeFrame(frame);
+    } else
+      removeFrames(id); // there should be only one frame with "id"
+  }
+}
+
 PropertyMap ID3v2::Tag::setProperties(const PropertyMap &origProps)
 {
   FrameList framesToDelete;
diff --git a/taglib/toolkit/tlist.h b/taglib/toolkit/tlist.h
index dce0e1c6..0099dad5 100644
--- a/taglib/toolkit/tlist.h
+++ b/taglib/toolkit/tlist.h
@@ -227,6 +227,11 @@ namespace TagLib {
      */
     bool operator==(const List<T> &l) const;
 
+    /*!
+     * Compares this list with \a l and returns true if the lists differ.
+     */
+    bool operator!=(const List<T> &l) const;
+
   protected:
     /*
      * If this List is being shared via implicit sharing, do a deep copy of the
diff --git a/taglib/toolkit/tlist.tcc b/taglib/toolkit/tlist.tcc
index a11887d8..37817f05 100644
--- a/taglib/toolkit/tlist.tcc
+++ b/taglib/toolkit/tlist.tcc
@@ -300,6 +300,12 @@ bool List<T>::operator==(const List<T> &l) const
   return d->list == l.d->list;
 }
 
+template <class T>
+bool List<T>::operator!=(const List<T> &l) const
+{
+  return d->list != l.d->list;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // protected members
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/taglib/toolkit/tpropertymap.cpp b/taglib/toolkit/tpropertymap.cpp
index 4868f2d0..8dab7756 100644
--- a/taglib/toolkit/tpropertymap.cpp
+++ b/taglib/toolkit/tpropertymap.cpp
@@ -20,7 +20,6 @@
  ***************************************************************************/
 
 #include "tpropertymap.h"
-
 using namespace TagLib;
 
 
@@ -90,18 +89,34 @@ PropertyMap::ConstIterator PropertyMap::find(const String &key) const
 bool PropertyMap::contains(const String &key) const
 {
   String realKey = prepareKey(key);
-  // we consider keys with empty value list as not present
-  if(realKey.isNull() || SimplePropertyMap::operator[](realKey).isEmpty())
+  if(realKey.isNull())
     return false;
   return SimplePropertyMap::contains(realKey);
 }
 
+bool PropertyMap::contains(const PropertyMap &other) const
+{
+  for(ConstIterator it = other.begin(); it != other.end(); ++it) {
+    if(!SimplePropertyMap::contains(it->first))
+      return false;
+    if ((*this)[it->first] != it->second)
+      return false;
+  }
+  return true;
+}
+
 PropertyMap &PropertyMap::erase(const String &key)
 {
   String realKey = prepareKey(key);
-  if(realKey.isNull())
-    return *this;
-  SimplePropertyMap::erase(realKey);
+  if(!realKey.isNull())
+    SimplePropertyMap::erase(realKey);
+  return *this;
+}
+
+PropertyMap &PropertyMap::erase(const PropertyMap &other)
+{
+  for(ConstIterator it = other.begin(); it != other.end(); ++it)
+    erase(it->first);
   return *this;
 }
 
@@ -126,6 +141,26 @@ StringList &PropertyMap::operator[](const String &key)
   return SimplePropertyMap::operator[](realKey);
 }
 
+bool PropertyMap::operator==(const PropertyMap &other) const
+{
+  for(ConstIterator it = other.begin(); it != other.end(); ++it) {
+    ConstIterator thisFind = find(it->first);
+    if( thisFind == end() || (thisFind->second != it->second) )
+      return false;
+  }
+  for(ConstIterator it = begin(); it != end(); ++it) {
+    ConstIterator otherFind = other.find(it->first);
+    if( otherFind == other.end() || (otherFind->second != it->second) )
+      return false;
+  }
+  return unsupported == other.unsupported;
+}
+
+bool PropertyMap::operator!=(const PropertyMap &other) const
+{
+  return !(*this == other);
+}
+
 void PropertyMap::removeEmpty()
 {
   StringList emptyKeys;