diff --git a/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreColor3f.h b/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreColor3f.h
index 801b2b4d0f..f239ddc308 100644
--- a/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreColor3f.h
+++ b/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreColor3f.h
@@ -66,7 +66,7 @@ public:
         PdmValueFieldSpecialization< cvf::Color3f >::setFromVariant(variantValue, value);
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return PdmValueFieldSpecialization< cvf::Color3f >::isEqual(variantValue, variantValue2);
     }
diff --git a/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreMat4d.h b/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreMat4d.h
index 6057fbe528..8a7664ca5a 100644
--- a/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreMat4d.h
+++ b/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreMat4d.h
@@ -64,7 +64,7 @@ public:
         PdmValueFieldSpecialization< cvf::Mat4d >::setFromVariant(variantValue, value);
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return PdmValueFieldSpecialization< cvf::Mat4d >::isEqual(variantValue, variantValue2);
     }
diff --git a/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreVec3d.h b/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreVec3d.h
index 2efd187fce..ce4db6748f 100644
--- a/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreVec3d.h
+++ b/Fwk/AppFwk/cafPdmCvf/cafPdmUiCoreVec3d.h
@@ -65,7 +65,7 @@ public:
         PdmValueFieldSpecialization< cvf::Vec3d >::setFromVariant(variantValue, value);
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return PdmValueFieldSpecialization< cvf::Vec3d >::isEqual(variantValue, variantValue2);
     }
diff --git a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmFieldTypeSpecializations.h b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmFieldTypeSpecializations.h
index 2587c68459..cabdfabf96 100644
--- a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmFieldTypeSpecializations.h
+++ b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmFieldTypeSpecializations.h
@@ -37,7 +37,7 @@ public:
         value.setRawPtr(variantValue.value<PdmPointer<PdmObjectHandle> >().rawPtr());
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return variantValue.value<PdmPointer<PdmObjectHandle> >() == variantValue2.value<PdmPointer<PdmObjectHandle> >() ;
     }
@@ -84,7 +84,7 @@ public:
         }
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return variantValue.value<T>() == variantValue2.value<T>();
     }
@@ -121,7 +121,7 @@ public:
         return PdmValueFieldSpecialization< std::vector<T> >::setFromVariant(variantValue, value);
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return variantValue.value<T>() == variantValue2.value<T>();
     }
@@ -174,7 +174,7 @@ public:
 #endif
     }
 
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return variantValue == variantValue2;
     }
diff --git a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmUiFieldCapability.inl b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmUiFieldCapability.inl
index 04daa76452..a29cfbf750 100644
--- a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmUiFieldCapability.inl
+++ b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafInternalPdmUiFieldCapability.inl
@@ -116,7 +116,11 @@ QVariant caf::PdmFieldUiCap<FieldType>::uiValue() const
         PdmOptionItemInfo::findValues<typename FieldType::FieldDataType>(m_optionEntryCache, uiBasedQVariant, indexesToFoundOptions);
         if (uiBasedQVariant.type() == QVariant::List)
         {
-            if (indexesToFoundOptions.size() == static_cast<size_t>(uiBasedQVariant.toList().size()))
+            if (isAutoAddingOptionFromValue() && indexesToFoundOptions.size() != static_cast<size_t>(uiBasedQVariant.toList().size())) 
+            {
+                assert(false); // Did not find all the field values among the options available, even though we should. The "core" data type in the field is probably not supported by QVariant::toString() 
+            }
+            else
             {
                 QList<QVariant> returnList;
                 for (size_t i = 0; i < indexesToFoundOptions.size(); ++i)
@@ -125,7 +129,6 @@ QVariant caf::PdmFieldUiCap<FieldType>::uiValue() const
                 }
                 return QVariant(returnList);
             }
-            assert(false); // Did not find all the field values among the options available.
         }
         else
         {
@@ -175,7 +178,8 @@ QList<PdmOptionItemInfo> caf::PdmFieldUiCap<FieldType>::valueOptions(bool* useOp
             bool foundAllFieldValues = PdmOptionItemInfo::findValues<typename FieldType::FieldDataType>(m_optionEntryCache, uiBasedQVariant, foundIndexes);
 
             // If not all are found, we have to add the missing to the list, to be able to show it
-
+            // This will only work if the field data type (or elemnt type for containers) is supported by QVariant.toString(). Custom classes don't
+             
             if (isAutoAddingOptionFromValue() && !foundAllFieldValues)
             {
                 if (uiBasedQVariant.type() != QVariant::List)  // Single value field
@@ -193,7 +197,10 @@ QList<PdmOptionItemInfo> caf::PdmFieldUiCap<FieldType>::valueOptions(bool* useOp
                         bool isFound = false;
                         for (unsigned int opIdx = 0; opIdx < static_cast<unsigned int>(m_optionEntryCache.size()); ++opIdx)
                         {
-                            if (valuesSelectedInField[i] == m_optionEntryCache[opIdx].value) isFound = true;
+                            if(PdmUiFieldSpecialization<typename FieldType::FieldDataType>::isDataElementEqual(valuesSelectedInField[i], m_optionEntryCache[opIdx].value))
+                            {
+                                isFound = true;
+                            }
                         }
 
                         if (!isFound && !valuesSelectedInField[i].toString().isEmpty())
diff --git a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldHandle.h b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldHandle.h
index 2d377d7f48..c195c2ab23 100644
--- a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldHandle.h
+++ b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldHandle.h
@@ -27,7 +27,7 @@ public:
     virtual QVariant toUiBasedQVariant() const                      { return QVariant(); }
     void             notifyFieldChanged(const QVariant& oldUiBasedQVariant, const QVariant& newUiBasedQVariant);
 
-    bool             isAutoAddingOptionFromValue()                    { return m_isAutoAddingOptionFromValue; }
+    bool             isAutoAddingOptionFromValue() const              { return m_isAutoAddingOptionFromValue; }
     void             setAutoAddingOptionFromValue(bool isAddingValue) { m_isAutoAddingOptionFromValue = isAddingValue;} 
 private:
     PdmFieldHandle*  m_owner;
diff --git a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldSpecialization.h b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldSpecialization.h
index 99c38d331b..6351b5f50c 100644
--- a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldSpecialization.h
+++ b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiFieldSpecialization.h
@@ -43,7 +43,7 @@ public:
     /// The == operator will normally work, but does not support custom types in the QVariant 
     /// See http://qt-project.org/doc/qt-4.8/qvariant.html#operator-eq-eq-64
     /// This is needed for the lookup regarding OptionValues
-    static bool isEqual(const QVariant& variantValue, const QVariant& variantValue2)
+    static bool isDataElementEqual(const QVariant& variantValue, const QVariant& variantValue2)
     {
         return variantValue == variantValue2; 
     }
diff --git a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiItem.h b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiItem.h
index 642d0e41eb..d2812e36ae 100644
--- a/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiItem.h
+++ b/Fwk/AppFwk/cafProjectDataModel/cafPdmUiCore/cafPdmUiItem.h
@@ -128,7 +128,7 @@ bool PdmOptionItemInfo::findValues(const QList<PdmOptionItemInfo>& optionList, Q
             {
                 for (unsigned int opIdx = 0; opIdx < static_cast<unsigned int>(optionList.size()); ++opIdx)
                 {
-                    if (PdmUiFieldSpecialization<T>::isEqual(valuesSelectedInField[i], optionList[opIdx].value))
+                    if (PdmUiFieldSpecialization<T>::isDataElementEqual(valuesSelectedInField[i], optionList[opIdx].value))
                     {
                         foundIndexes.push_back(opIdx);
                     }
@@ -142,7 +142,7 @@ bool PdmOptionItemInfo::findValues(const QList<PdmOptionItemInfo>& optionList, Q
     {
         for (unsigned int opIdx = 0; opIdx < static_cast<unsigned int>(optionList.size()); ++opIdx)
         {
-            if (PdmUiFieldSpecialization<T>::isEqual(optionList[opIdx].value, fieldValue))
+            if (PdmUiFieldSpecialization<T>::isDataElementEqual(optionList[opIdx].value, fieldValue))
             {
                 foundIndexes.push_back(opIdx);
                 break;