diff --git a/eeschema/dialogs/dialog_symbol_properties.cpp b/eeschema/dialogs/dialog_symbol_properties.cpp
index 991345310d..1556681569 100644
--- a/eeschema/dialogs/dialog_symbol_properties.cpp
+++ b/eeschema/dialogs/dialog_symbol_properties.cpp
@@ -729,8 +729,8 @@ bool DIALOG_SYMBOL_PROPERTIES::TransferDataFromWindow()
         }
     }
 
-    // The value, footprint and datasheet fields, alternate pin assignements, and include/exclude
-    // flags should be kept in sync in multi-unit parts.
+    // Keep fields other than the reference, include/exclude flags, and alternate pin assignements
+    // in sync in multi-unit parts.
     if( m_symbol->GetUnitCount() > 1 && m_symbol->IsAnnotated( &GetParent()->GetCurrentSheet() ) )
     {
         wxString ref = m_symbol->GetRef( &GetParent()->GetCurrentSheet() );
@@ -751,7 +751,30 @@ bool DIALOG_SYMBOL_PROPERTIES::TransferDataFromWindow()
                                                  appendUndo );
                 otherUnit->SetValue( m_fields->at( VALUE_FIELD ).GetText() );
                 otherUnit->SetFootprint( m_fields->at( FOOTPRINT_FIELD ).GetText() );
-                otherUnit->GetField( DATASHEET_FIELD )->SetText( m_fields->at( DATASHEET_FIELD ).GetText() );
+
+                for( size_t ii = DATASHEET_FIELD; ii < m_fields->size(); ++ii )
+                {
+                    SCH_FIELD* otherField = otherUnit->FindField( m_fields->at( ii ).GetName() );
+
+                    if( otherField )
+                    {
+                        otherField->SetText( m_fields->at( ii ).GetText() );
+                    }
+                    else
+                    {
+                        SCH_FIELD* newField = otherUnit->AddField( m_fields->at( ii ) );
+                        const_cast<KIID&>( newField->m_Uuid ) = KIID();
+                    }
+                }
+
+                for( size_t ii = otherUnit->GetFields().size() - 1; ii > DATASHEET_FIELD; ii-- )
+                {
+                    SCH_FIELD& otherField = otherUnit->GetFields().at( ii );
+
+                    if( !m_symbol->FindField( otherField.GetName() ) )
+                        otherUnit->GetFields().erase( otherUnit->GetFields().begin() + ii );
+                }
+
                 otherUnit->SetIncludeInBom( !m_cbExcludeFromBom->IsChecked() );
                 otherUnit->SetIncludeOnBoard( !m_cbExcludeFromBoard->IsChecked() );
 
diff --git a/eeschema/sch_symbol.h b/eeschema/sch_symbol.h
index 73599aafae..248d2b5ed7 100644
--- a/eeschema/sch_symbol.h
+++ b/eeschema/sch_symbol.h
@@ -695,13 +695,13 @@ private:
      */
     wxString    m_schLibSymbolName;
 
-    TRANSFORM   m_transform;    ///< The rotation/mirror transformation matrix.
-    SCH_FIELDS  m_fields;       ///< Variable length list of fields.
+    TRANSFORM                              m_transform; ///< The rotation/mirror transformation.
+    std::vector<SCH_FIELD>                 m_fields;    ///< Variable length list of fields.
 
-    std::unique_ptr< LIB_SYMBOL >          m_part;    // a flattened copy of the LIB_SYMBOL from
-                                                      // the PROJECT's libraries.
-    std::vector<std::unique_ptr<SCH_PIN>>  m_pins;    // a SCH_PIN for every LIB_PIN (all units)
-    std::unordered_map<LIB_PIN*, unsigned> m_pinMap;  // library pin pointer to SCH_PIN's index
+    std::unique_ptr< LIB_SYMBOL >          m_part;      ///< a flattened copy of the LIB_SYMBOL
+                                                        ///<   from the PROJECT's libraries.
+    std::vector<std::unique_ptr<SCH_PIN>>  m_pins;      ///< a SCH_PIN for every LIB_PIN (all units)
+    std::unordered_map<LIB_PIN*, unsigned> m_pinMap;    ///< library pin pointer : SCH_PIN's index
 
     bool        m_isInNetlist;  ///< True if the symbol should appear in the netlist
     bool        m_inBom;        ///< True to include in bill of materials export.