use new features model instead of valuerelation model in qml

src/quickgui/plugin/editor/qgsquickeditorwidgetcombobox.qml

@@ -26,6 +26,7 @@ ComboBox {
   id: comboBox
 
   property var comboStyle
+  signal itemClicked( var index )
   anchors { left: parent.left; right: parent.right }
 
   MouseArea {
@@ -47,8 +48,9 @@ ComboBox {
     text: model.display
     font.weight: comboBox.currentIndex === index ? Font.DemiBold : Font.Normal
     font.pixelSize: comboStyle.fontPixelSize
-    highlighted: comboBox.highlightedIndex == index
+    highlighted: comboBox.highlightedIndex === index
     leftPadding: 5 * QgsQuick.Utils.dp
+    onClicked: comboBox.itemClicked( model.EmitableIndex ? model.EmitableIndex : index )
   }
 
   contentItem: Text {

src/quickgui/plugin/editor/qgsquickvaluerelation.qml

@@ -26,6 +26,14 @@ import QgsQuick 0.1 as QgsQuick
 Item {
   signal valueChanged(var value, bool isNull)
 
+  function itemSelected( index ) {
+    combobox.itemClicked( index )
+  }
+
+  function openCombobox() {
+    combobox.popup.open()
+  }
+
   id: fieldItem
   enabled: !readOnly
   height: customStyle.fields.height
@@ -36,31 +44,45 @@ Item {
   }
 
   QgsQuick.EditorWidgetComboBox {
-
+    id: combobox
     property var currentEditorValue: value
 
     comboStyle: customStyle.fields
     textRole: 'display'
     height: parent.height
 
-    model: QgsQuick.ValueRelationListModel {
-        id: vrModel
+    model: QgsQuick.FeaturesListModel {
+      id: vrModel
+      modelType: QgsQuick.FeaturesListModel.ValueRelation
+
+      // recalculate index when model changes
+      onModelReset: {
+        combobox.currentIndex = vrModel.rowIndexFromKeyModel( value )
+      }
     }
 
     Component.onCompleted: {
         vrModel.populate(config)
-        currentIndex = vrModel.rowForKey(value);
+        currentIndex = vrModel.rowIndexFromKeyModel( value )
+    }
+
+    onPressedChanged: {
+      if( pressed )
+      {
+        customWidget.valueRelationOpened( fieldItem, vrModel )
+        pressed = false // we close combobox and let custom handler react, it can open combobox via openCombobox()
+      }
     }
 
     // Called when user makes selection in the combo box
-    onCurrentIndexChanged: {
-      valueChanged(vrModel.keyForRow(currentIndex), false)
+    onItemClicked: {
+        currentIndex = vrModel.rowIndexFromKeyModel( index )
+        valueChanged( index, false )
     }
 
     // Called when the same form is used for a different feature
     onCurrentEditorValueChanged: {
-        currentIndex = vrModel.rowForKey(value);
+        currentIndex = vrModel.rowIndexFromKeyModel( value );
     }
-
   }
 }

src/quickgui/plugin/qgsquickfeatureform.qml

@@ -36,6 +36,16 @@ Item {
    */
   signal canceled
 
+  /**
+    */
+  property var customWidgetCallback: QtObject {
+
+    property var valueRelationOpened: function valueRelationOpened( widget, valueRelationModel ) {
+      // by default just open combobox
+      widget.openCombobox()
+    }
+  }
+
    /**
     * A handler for extra events in externalSourceWidget.
     */
@@ -396,6 +406,7 @@ Item {
           property bool readOnly: form.state == "ReadOnly" || !AttributeEditable
           property var featurePair: form.model.attributeModel.featureLayerPair
           property var activeProject: form.project
+          property var customWidget: form.customWidgetCallback
 
           active: widget !== 'Hidden'
 

src/quickgui/plugin/qgsquickplugin.cpp

@@ -47,6 +47,7 @@
 #include "qgsquicksubmodel.h"
 #include "qgsquickutils.h"
 #include "qgsquickvaluerelationlistmodel.h"
+#include "qgsquickfeatureslistmodel.h"
 
 static QObject *_utilsProvider( QQmlEngine *engine, QJSEngine *scriptEngine )
 {
@@ -73,7 +74,6 @@ void QgsQuickPlugin::registerTypes( const char *uri )
   qRegisterMetaType< QVariant::Type >( "QVariant::Type" );
 
   qmlRegisterUncreatableType< QgsUnitTypes >( uri, 0, 1, "QgsUnitTypes", "Only enums from QgsUnitTypes can be used" );
-
   qmlRegisterType< QgsProject >( uri, 0, 1, "Project" );
   qmlRegisterType< QgsQuickAttributeFormModel >( uri, 0, 1, "AttributeFormModel" );
   qmlRegisterType< QgsQuickAttributeModel >( uri, 0, 1, "AttributeModel" );
@@ -89,6 +89,7 @@ void QgsQuickPlugin::registerTypes( const char *uri )
   qmlRegisterType< QgsQuickSubModel >( uri, 0, 1, "SubModel" );
   qmlRegisterType< QgsVectorLayer >( uri, 0, 1, "VectorLayer" );
   qmlRegisterType< QgsQuickValueRelationListModel > ( uri, 0, 1, "ValueRelationListModel" );
+  qmlRegisterType< QgsQuickFeaturesListModel >( uri, 0, 1, "FeaturesListModel" );
 
   qmlRegisterSingletonType< QgsQuickUtils >( uri, 0, 1, "Utils", _utilsProvider );
 }