diff --git a/src/Mod/PartDesign/App/AppPartDesign.cpp b/src/Mod/PartDesign/App/AppPartDesign.cpp
index 0922ad5ea..98782e7a2 100644
--- a/src/Mod/PartDesign/App/AppPartDesign.cpp
+++ b/src/Mod/PartDesign/App/AppPartDesign.cpp
@@ -101,4 +101,8 @@ PyMODINIT_FUNC init_PartDesign()
     PartDesign::Plane              ::init();
     PartDesign::Line               ::init();
     PartDesign::Point              ::init();
+
+    PartDesign::Point::initHints();
+    PartDesign::Line ::initHints();
+    PartDesign::Plane::initHints();
 }
diff --git a/src/Mod/PartDesign/App/DatumFeature.cpp b/src/Mod/PartDesign/App/DatumFeature.cpp
index 0d4148f59..75a95ca53 100644
--- a/src/Mod/PartDesign/App/DatumFeature.cpp
+++ b/src/Mod/PartDesign/App/DatumFeature.cpp
@@ -43,8 +43,11 @@
 #endif
 
 
+#include <App/Plane.h>
 #include "DatumFeature.h"
 #include <Base/Tools.h>
+#include <Base/Exception.h>
+#include "Mod/Part/App/PrimitiveFeature.h"
 
 #ifndef M_PI
 #define M_PI       3.14159265358979323846
@@ -52,7 +55,6 @@
 
 using namespace PartDesign;
 
-
 PROPERTY_SOURCE_ABSTRACT(PartDesign::Datum, PartDesign::Feature)
 
 Datum::Datum(void)
@@ -77,13 +79,174 @@ short Datum::mustExecute(void) const
 void Datum::onChanged(const App::Property* prop)
 {
 
+    if (prop == &References) {
+        refTypes.clear();
+        std::vector<App::DocumentObject*> refs = References.getValues();
+        std::vector<std::string> refnames = References.getSubValues();
+
+        for (int r = 0; r < refs.size(); r++)
+            refTypes.insert(getRefType(refs[r], refnames[r]));
+    }
+
     PartDesign::Feature::onChanged(prop);
 }
 
+// Note: We don't distinguish between e.g. datum lines and edges here
+// These values are just markers so it doesn't matter that they are Part features
+#define PLANE Part::Plane::getClassTypeId()
+#define LINE  Part::Line::getClassTypeId()
+#define POINT Part::Vertex::getClassTypeId()
+
+const Base::Type Datum::getRefType(const App::DocumentObject* obj, const std::string& subname)
+{
+    Base::Type type = obj->getTypeId();
+
+    if ((type == App::Plane::getClassTypeId()) || (type == PartDesign::Plane::getClassTypeId()))
+        return PLANE;
+    else if (type == PartDesign::Line::getClassTypeId())
+        return LINE;
+    else if (type == PartDesign::Point::getClassTypeId())
+        return POINT;
+    else if (type.isDerivedFrom(Part::Feature::getClassTypeId())) {
+        // Note: For now, only planar references are possible
+        if (subname.size() > 4 && subname.substr(0,4) == "Face")
+            return PLANE;
+        else if (subname.size() > 4 && subname.substr(0,4) == "Edge")
+            return LINE;
+        else if (subname.size() > 6 && subname.substr(0,6) == "Vertex")
+            return POINT;
+    }
+
+    throw Base::Exception("PartDesign::Datum::getRefType(): Illegal object type");
+}
+
+// ================================ Initialize the hints =====================
+
+std::map<std::multiset<Base::Type>, std::set<Base::Type> > Point::hints = std::map<std::multiset<Base::Type>, std::set<Base::Type> >();
+
+void Point::initHints()
+{
+    std::set<Base::Type> DONE;
+    DONE.insert(PartDesign::Point::getClassTypeId());
+
+    std::multiset<Base::Type> key;
+    std::set<Base::Type> value;
+    key.insert(POINT);
+    hints[key] = DONE; // POINT -> DONE. Point from another point or vertex
+
+    key.clear(); value.clear();
+    key.insert(LINE);
+    value.insert(LINE); value.insert(PLANE);
+    hints[key] = value; // LINE -> LINE or PLANE
+
+    key.clear(); value.clear();
+    key.insert(LINE); key.insert(LINE);
+    hints[key] = DONE; // {LINE, LINE} -> DONE. Point from two lines or edges
+
+    key.clear(); value.clear();
+    key.insert(LINE); key.insert(PLANE);
+    hints[key] = DONE; // {LINE, PLANE} -> DONE. Point from line and plane
+
+    key.clear(); value.clear();
+    key.insert(PLANE);
+    value.insert(PLANE); value.insert(LINE);
+    hints[key] = value; // PLANE -> PLANE or LINE
+
+    key.clear(); value.clear();
+    key.insert(PLANE); key.insert(PLANE);
+    value.insert(PLANE);
+    hints[key] = value; // {PLANE, PLANE} -> PLANE
+
+    key.clear(); value.clear();
+    key.insert(PLANE); key.insert(PLANE); key.insert(PLANE);
+    hints[key] = DONE; // {PLANE, PLANE, PLANE} -> DONE. Point from three planes
+
+    key.clear(); value.clear();
+    value.insert(POINT); value.insert(LINE); value.insert(PLANE);
+    hints[key] = value;
+}
+
+std::map<std::multiset<Base::Type>, std::set<Base::Type> > Line::hints = std::map<std::multiset<Base::Type>, std::set<Base::Type> >();
+
+void Line::initHints()
+{
+    std::set<Base::Type> DONE;
+    DONE.insert(PartDesign::Line::getClassTypeId());
+
+    std::multiset<Base::Type> key;
+    std::set<Base::Type> value;
+    key.insert(LINE);
+    hints[key] = DONE; // LINE -> DONE. Line from another line or edge
+
+    key.clear(); value.clear();
+    key.insert(POINT);
+    value.insert(POINT);
+    hints[key] = value; // POINT -> POINT
+
+    key.clear(); value.clear();
+    key.insert(POINT); key.insert(POINT);
+    hints[key] = DONE; // {POINT, POINT} -> DONE. Line from two points or vertices
+
+    key.clear(); value.clear();
+    key.insert(PLANE);
+    value.insert(PLANE);
+    hints[key] = value; // PLANE -> PLANE
+
+    key.clear(); value.clear();
+    key.insert(PLANE); key.insert(PLANE);
+    hints[key] = DONE; // {PLANE, PLANE} -> DONE. Line from two planes or faces
+
+    key.clear(); value.clear();
+    value.insert(POINT); value.insert(LINE); value.insert(PLANE);
+    hints[key] = value;
+}
+
+std::map<std::multiset<Base::Type>, std::set<Base::Type> > Plane::hints = std::map<std::multiset<Base::Type>, std::set<Base::Type> >();
+
+void Plane::initHints()
+{
+    std::set<Base::Type> DONE;
+    DONE.insert(PartDesign::Plane::getClassTypeId());
+
+    std::multiset<Base::Type> key;
+    std::set<Base::Type> value;
+    key.insert(PLANE);
+    hints[key] = DONE; // PLANE -> DONE. Plane from another plane or face
+
+    key.clear(); value.clear();
+    key.insert(POINT);
+    value.insert(POINT); value.insert(LINE);
+    hints[key] = value; // POINT -> POINT or LINE
+
+    key.clear(); value.clear();
+    key.insert(POINT); key.insert(LINE);
+    hints[key] = DONE; // {POINT, LINE} -> DONE. Plane from point/vertex and line/edge
+
+    key.clear(); value.clear();
+    key.insert(POINT); key.insert(POINT);
+    value.insert(POINT);
+    hints[key] = value; // {POINT, POINT} -> POINT
+
+    key.clear(); value.clear();
+    key.insert(POINT); key.insert(POINT); key.insert(POINT);
+    hints[key] = DONE; // {POINT, POINT, POINT} -> DONE. Plane from 3 points or vertices
+
+    key.clear(); value.clear();
+    key.insert(LINE);
+    value.insert(POINT);
+    hints[key] = value; // LINE -> POINT
+
+    key.clear(); value.clear();
+    value.insert(POINT); value.insert(LINE); value.insert(PLANE);
+    hints[key] = value;
+}
+
+// ============================================================================
+
 PROPERTY_SOURCE(PartDesign::Point, PartDesign::Datum)
 
 Point::Point()
-{
+{    
 }
 
 Point::~Point()
@@ -97,8 +260,43 @@ short Point::mustExecute() const
 
 App::DocumentObjectExecReturn *Point::execute(void)
 {
+    std::set<Base::Type> hint = getHint();
+    if (!((hint.size() == 1) && (hint.find(PartDesign::Point::getClassTypeId()) != hint.end())))
+        return App::DocumentObject::StdReturn; // incomplete references
+
+    // Extract the shapes of the references
+    std::vector<TopoDS_Shape> shapes;
+    std::vector<App::DocumentObject*> refs = References.getValues();
+    std::vector<std::string> refnames = References.getSubValues();
+    for (int i = 0; i < refs.size(); i++) {
+        if (!refs[i]->getTypeId().isDerivedFrom(Part::Feature::getClassTypeId()))
+            return new App::DocumentObjectExecReturn("PartDesign::Point: Invalid reference type");
+        Part::Feature* feature = static_cast<Part::Feature*>(refs[i]);
+        const TopoDS_Shape& sh = feature->Shape.getValue();
+        if (sh.IsNull())
+            return new App::DocumentObjectExecReturn("PartDesign::Point: Reference has NULL shape");
+        if (refnames[i].empty()) {
+            // Datum feature or App::Plane
+            shapes.push_back(sh);
+        } else {
+            // Get subshape
+            TopoDS_Shape subshape = feature->Shape.getShape().getSubShape(refnames[i].c_str());
+            if (subshape.IsNull())
+                return new App::DocumentObjectExecReturn("PartDesign::Point: Reference has NULL subshape");
+            shapes.push_back(subshape);
+        }
+    }
+
+    // Find the point
     gp_Pnt point(0,0,0);
-    // TODO: Find the point
+
+    if (shapes.size() == 1) {
+        // Point from vertex or other point
+        if (shapes[0].ShapeType() != TopAbs_VERTEX)
+            return new App::DocumentObjectExecReturn("PartDesign::Point::execute(): Internal error, unexpected ShapeType");
+        TopoDS_Vertex v = TopoDS::Vertex(shapes[0]);
+        //point.X = v.
+    }
     
     BRepBuilderAPI_MakeVertex MakeVertex(point);
     const TopoDS_Vertex& vertex = MakeVertex.Vertex();
@@ -108,6 +306,15 @@ App::DocumentObjectExecReturn *Point::execute(void)
 }
 
 
+const std::set<Base::Type> Point::getHint()
+{
+    if (hints.find(refTypes) != hints.end())
+        return hints[refTypes];
+    else
+        return std::set<Base::Type>();
+}
+
+
 PROPERTY_SOURCE(PartDesign::Line, PartDesign::Datum)
 
 Line::Line()
@@ -139,6 +346,15 @@ App::DocumentObjectExecReturn *Line::execute(void)
 }
 
 
+const std::set<Base::Type> Line::getHint()
+{
+    if (hints.find(refTypes) != hints.end())
+        return hints[refTypes];
+    else
+        return std::set<Base::Type>();
+}
+
+
 PROPERTY_SOURCE(PartDesign::Plane, PartDesign::Datum)
 
 Plane::Plane()
@@ -172,3 +388,12 @@ App::DocumentObjectExecReturn *Plane::execute(void)
 
     return App::DocumentObject::StdReturn;
 }
+
+
+const std::set<Base::Type> Plane::getHint()
+{
+    if (hints.find(refTypes) != hints.end())
+        return hints[refTypes];
+    else
+        return std::set<Base::Type>();
+}
diff --git a/src/Mod/PartDesign/App/DatumFeature.h b/src/Mod/PartDesign/App/DatumFeature.h
index e0c26a62c..7e4f6d7a8 100644
--- a/src/Mod/PartDesign/App/DatumFeature.h
+++ b/src/Mod/PartDesign/App/DatumFeature.h
@@ -53,10 +53,18 @@ public:
     const char* getViewProviderName(void) const {
         return "PartDesignGui::ViewProviderDatum";
     }
-    //@}
+    //@}    
+
+    virtual const std::set<Base::Type> getHint() = 0;
 
 protected:
     void onChanged (const App::Property* prop);
+
+protected:
+    std::multiset<Base::Type> refTypes;
+
+    static const Base::Type getRefType(const App::DocumentObject* obj, const std::string& subname);
+
 };
 
 class PartDesignExport Point : public PartDesign::Datum
@@ -73,6 +81,13 @@ public:
     App::DocumentObjectExecReturn *execute(void);
     short mustExecute() const;
     //@}
+
+    static void initHints();
+    const std::set<Base::Type> getHint();
+
+private:
+    // Hints on what further references are required/possible on this feature for a given set of references
+    static std::map<std::multiset<Base::Type>, std::set<Base::Type> > hints;
 };
 
 class PartDesignExport Line : public PartDesign::Datum
@@ -89,6 +104,13 @@ public:
     App::DocumentObjectExecReturn *execute(void);
     short mustExecute() const;
     //@}
+
+    static void initHints();
+    const std::set<Base::Type> getHint();
+
+private:
+    // Hints on what further references are required/possible on this feature for a given set of references
+    static std::map<std::multiset<Base::Type>, std::set<Base::Type> > hints;
 };
 
 class PartDesignExport Plane : public PartDesign::Datum
@@ -104,6 +126,13 @@ public:
     App::DocumentObjectExecReturn *execute(void);
     short mustExecute() const;
     //@}
+
+    static void initHints();
+    const std::set<Base::Type> getHint();
+
+private:
+    // Hints on what further references are required/possible on this feature for a given set of references
+    static std::map<std::multiset<Base::Type>, std::set<Base::Type> > hints;
 };
 
 } //namespace PartDesign
diff --git a/src/Mod/PartDesign/Gui/Command.cpp b/src/Mod/PartDesign/Gui/Command.cpp
index bd564aad2..ca74c343c 100644
--- a/src/Mod/PartDesign/Gui/Command.cpp
+++ b/src/Mod/PartDesign/Gui/Command.cpp
@@ -433,7 +433,7 @@ void CmdPartDesignPoint::activated(int iMsg)
     QString refStr = getReferenceString(this);
     PartDesign::Body *pcActiveBody = PartDesignGui::getBody();
 
-    openCommand("Create a datum plane");
+    openCommand("Create a datum point");
     doCommand(Doc,"App.activeDocument().addObject('PartDesign::Point','%s')",FeatName.c_str());
     if (refStr.length() > 0)
         doCommand(Doc,"App.activeDocument().%s.References = %s",FeatName.c_str(),refStr.toStdString().c_str());
diff --git a/src/Mod/PartDesign/Gui/TaskDatumParameters.cpp b/src/Mod/PartDesign/Gui/TaskDatumParameters.cpp
index d4637ae86..46e114f56 100644
--- a/src/Mod/PartDesign/Gui/TaskDatumParameters.cpp
+++ b/src/Mod/PartDesign/Gui/TaskDatumParameters.cpp
@@ -44,6 +44,7 @@
 #include <Base/Console.h>
 #include <Gui/Selection.h>
 #include <Gui/Command.h>
+#include <Mod/Part/App/PrimitiveFeature.h>
 #include <Mod/PartDesign/App/DatumFeature.h>
 #include <Mod/PartDesign/App/Body.h>
 #include "ReferenceSelection.h"
@@ -95,9 +96,10 @@ void TaskDatumParameters::makeRefStrings(std::vector<QString>& refstrings, std::
 }
 
 TaskDatumParameters::TaskDatumParameters(ViewProviderDatum *DatumView,QWidget *parent)
-    : TaskBox(Gui::BitmapFactory().pixmap("iconName"),tr("Datum parameters"),true, parent),DatumView(DatumView)
-{    
-    TaskBox(Gui::BitmapFactory().pixmap((QString::fromAscii("PartDesign_") + DatumView->datumType).toAscii()), DatumView->datumType + tr(" parameters"), true, parent);
+    : TaskBox(Gui::BitmapFactory().pixmap((QString::fromAscii("PartDesign_") + DatumView->datumType).toAscii()),
+              DatumView->datumType + tr(" parameters"), true, parent),
+      DatumView(DatumView)
+{
     // we need a separate container widget to add all controls to
     proxy = new QWidget(this);
     ui = new Ui_TaskDatumParameters();
@@ -135,16 +137,18 @@ TaskDatumParameters::TaskDatumParameters(ViewProviderDatum *DatumView,QWidget *p
 
     // Get the feature data    
     PartDesign::Datum* pcDatum = static_cast<PartDesign::Datum*>(DatumView->getObject());
+    std::vector<App::DocumentObject*> refs = pcDatum->References.getValues();
     std::vector<std::string> refnames = pcDatum->References.getSubValues();
-    std::vector<QString> refstrings;
-    makeRefStrings(refstrings, refnames);
+
 
     //bool checked1 = pcDatum->Checked.getValue();
-    std::vector<float> vals = pcDatum->Values.getValues();
+    std::vector<double> vals = pcDatum->Values.getValues();
 
     // Fill data into dialog elements
     ui->spinValue1->setValue(vals[0]);
     //ui->checkBox1->setChecked(checked1);
+    std::vector<QString> refstrings;
+    makeRefStrings(refstrings, refnames);
     ui->lineRef1->setText(refstrings[0]);
     ui->lineRef1->setProperty("RefName", QByteArray(refnames[0].c_str()));
     ui->lineRef2->setText(refstrings[1]);
@@ -164,10 +168,96 @@ TaskDatumParameters::TaskDatumParameters(ViewProviderDatum *DatumView,QWidget *p
     updateUI();
 }
 
+const QString makeRefText(std::set<Base::Type> hint)
+{
+    QString result;
+    for (std::set<Base::Type>::const_iterator t = hint.begin(); t != hint.end(); t++) {
+        QString tText;
+        if (((*t) == Part::Plane::getClassTypeId()) || ((*t) == PartDesign::Plane::getClassTypeId()))
+            tText = QObject::tr("Plane");
+        else if (((*t) == Part::Line::getClassTypeId()) || ((*t) == PartDesign::Line::getClassTypeId()))
+            tText = QObject::tr("Line");
+        else if (((*t) == Part::Vertex::getClassTypeId()) || ((*t) == PartDesign::Point::getClassTypeId()))
+            tText = QObject::tr("Point");
+        result += QString::fromAscii(result.size() == 0 ? "" : "/") + tText;
+    }
+
+    return result;
+}
+
 void TaskDatumParameters::updateUI()
 {
     ui->checkBox1->setEnabled(false);
-    onButtonRef1(true);
+
+    PartDesign::Datum* pcDatum = static_cast<PartDesign::Datum*>(DatumView->getObject());
+    std::vector<App::DocumentObject*> refs = pcDatum->References.getValues();
+    completed = false;
+
+    if (refs.size() == 3) {
+        onButtonRef1(false); // No more references required
+        completed = true;
+        return;
+    }
+
+    // Get hints for further required references
+    std::set<Base::Type> hint = pcDatum->getHint();
+    if (hint == std::set<Base::Type>()) {
+        QMessageBox::warning(this, tr("Illegal selection"), tr("This feature cannot be created with this combination of references"));
+        if (refs.size() == 1) {
+            onButtonRef1(true);
+        } else if (refs.size() == 2) {
+            onButtonRef2(true);
+        } else if (refs.size() == 3) {
+            onButtonRef3(true);
+        }
+        return;
+    }
+
+    // Enable the next reference button
+    if (refs.size() == 0) {
+        ui->buttonRef2->setEnabled(false);
+        ui->lineRef2->setEnabled(false);
+        ui->buttonRef3->setEnabled(false);
+        ui->lineRef3->setEnabled(false);
+    } else if (refs.size() == 1) {
+        ui->buttonRef2->setEnabled(true);
+        ui->lineRef2->setEnabled(true);
+        ui->buttonRef3->setEnabled(false);
+        ui->lineRef3->setEnabled(false);
+    } else if (refs.size() == 2) {
+        ui->buttonRef2->setEnabled(true);
+        ui->lineRef2->setEnabled(true);
+        ui->buttonRef3->setEnabled(true);
+        ui->lineRef3->setEnabled(true);
+    }
+
+    QString refText = makeRefText(hint);
+
+    // Check if we have all required references
+    if (refText == DatumView->datumType) {
+        if (refs.size() == 1) {
+            ui->buttonRef2->setEnabled(false);
+            ui->lineRef2->setEnabled(false);
+            ui->buttonRef3->setEnabled(false);
+            ui->lineRef3->setEnabled(false);
+        } else if (refs.size() == 2) {
+            ui->buttonRef3->setEnabled(false);
+            ui->lineRef3->setEnabled(false);
+        }
+        onButtonRef1(false); // No more references required
+        completed = true;
+        return;
+    }
+
+    if (refs.size() == 0) {
+        onButtonRef1(true);
+    } else if (refs.size() == 1) {
+        ui->buttonRef2->setText(refText);
+        onButtonRef2(true);
+    } else if (refs.size() == 2) {
+        ui->buttonRef3->setText(refText);
+        onButtonRef3(true);
+    }
 }
 
 QLineEdit* TaskDatumParameters::getLine(const int idx)
@@ -196,7 +286,7 @@ void TaskDatumParameters::onSelectionChanged(const Gui::SelectionChanges& msg)
         if (selObj == pcDatum) return;
         std::string subname = msg.pSubName;
 
-        // Remove subname for planes
+        // Remove subname for planes and datum features
         if (selObj->getTypeId().isDerivedFrom(App::Plane::getClassTypeId()) ||
             selObj->getTypeId().isDerivedFrom(PartDesign::Datum::getClassTypeId()))
             subname = "";
@@ -224,15 +314,14 @@ void TaskDatumParameters::onSelectionChanged(const Gui::SelectionChanges& msg)
             line->blockSignals(false);
         }
 
-        // Turn off reference selection mode
-        onButtonRef1(false); // Note: It doesn't matter whether we call onButtonRef1 or onButtonRef2 etc.
+        updateUI();
     }
 }
 
 void TaskDatumParameters::onValue1Changed(double val)
 {
     PartDesign::Datum* pcDatum = static_cast<PartDesign::Datum*>(DatumView->getObject());
-    std::vector<float> vals = pcDatum->Values.getValues();
+    std::vector<double> vals = pcDatum->Values.getValues();
     vals[0] = val;
     pcDatum->Values.setValues(vals);
     pcDatum->getDocument()->recomputeFeature(pcDatum);
@@ -307,30 +396,28 @@ void TaskDatumParameters::onRefName(const QString& text, const int idx)
         ui->lineRef2->setProperty("RefName", QByteArray(newrefnames[1].c_str()));
         ui->lineRef3->setText(refstrings[2]);
         ui->lineRef3->setProperty("RefName", QByteArray(newrefnames[2].c_str()));
+        updateUI();
         return;
     }
 
+    QStringList parts = text.split(QChar::fromAscii(':'));
+    if (parts.length() < 2)
+        parts.push_back(QString::fromAscii(""));
     // Check whether this is the name of an App::Plane or PartDesign::Datum feature
-    App::DocumentObject* obj = DatumView->getObject()->getDocument()->getObject(text.toAscii());
-    std::string subElement = "";
+    App::DocumentObject* obj = DatumView->getObject()->getDocument()->getObject(parts[0].toAscii());
+    if (obj == NULL) return;
 
-    if (obj != NULL) {
-        if (!obj->getTypeId().isDerivedFrom(App::Plane::getClassTypeId())) {
-            if (!obj->getTypeId().isDerivedFrom(PartDesign::Datum::getClassTypeId()))
-                return;
+    std::string subElement;
 
-            if (!PartDesignGui::ActivePartObject->hasFeature(obj))
-                return;
-        } // else everything is OK (we assume a Part can only have exactly 3 App::Plane objects located at the base of the feature tree)
-    } else {
-        // This is the name of a subelement of the visible solid (Face, Edge, Vertex)
-        App::DocumentObject* solid = PartDesignGui::ActivePartObject->getPrevSolidFeature();
-        if (solid == NULL) {
-            // There is no solid, so we can't select from it...
+    if (obj->getTypeId().isDerivedFrom(App::Plane::getClassTypeId())) {
+        // everything is OK (we assume a Part can only have exactly 3 App::Plane objects located at the base of the feature tree)
+        subElement = "";
+    } else if (obj->getTypeId().isDerivedFrom(PartDesign::Datum::getClassTypeId())) {
+        if (!PartDesignGui::ActivePartObject->hasFeature(obj))
             return;
-        }
-
-        // TODO: check validity of the text that was entered: Does it actually reference an element on the solid?
+        subElement = "";
+    } else {
+        // TODO: check validity of the text that was entered: Does subElement actually reference to an element on the obj?
 
         // We must expect that "text" is the translation of "Face", "Edge" or "Vertex" followed by an ID.
         QString name;
@@ -339,7 +426,7 @@ void TaskDatumParameters::onRefName(const QString& text, const int idx)
         std::stringstream ss;
 
         str << "^" << tr("Face") << "(\\d+)$";
-        if (text.indexOf(rx) < 0) {
+        if (parts[1].indexOf(rx) < 0) {
             line->setProperty("RefName", QByteArray());
             return;
         } else {
@@ -347,7 +434,7 @@ void TaskDatumParameters::onRefName(const QString& text, const int idx)
             ss << "Face" << faceId;
         }
         str << "^" << tr("Edge") << "(\\d+)$";
-        if (text.indexOf(rx) < 0) {
+        if (parts[1].indexOf(rx) < 0) {
             line->setProperty("RefName", QByteArray());
             return;
         } else {
@@ -355,7 +442,7 @@ void TaskDatumParameters::onRefName(const QString& text, const int idx)
             ss << "Edge" << lineId;
         }
         str << "^" << tr("Vertex") << "(\\d+)$";
-        if (text.indexOf(rx) < 0) {
+        if (parts[1].indexOf(rx) < 0) {
             line->setProperty("RefName", QByteArray());
             return;
         } else {
@@ -377,6 +464,7 @@ void TaskDatumParameters::onRefName(const QString& text, const int idx)
         refnames.push_back(subElement.c_str());
     }
     pcDatum->References.setValues(refs, refnames);
+    updateUI();
     //pcDatum->getDocument()->recomputeFeature(pcDatum);
 }
 
@@ -451,6 +539,7 @@ void TaskDatumParameters::changeEvent(QEvent *e)
         ui->lineRef1->setText(refstrings[0]);
         ui->lineRef2->setText(refstrings[1]);
         ui->lineRef3->setText(refstrings[2]);
+        // TODO: Translate DatumView->datumType ?
 
         ui->spinValue1->blockSignals(false);
         ui->checkBox1->blockSignals(false);
@@ -497,6 +586,11 @@ void TaskDlgDatumParameters::clicked(int)
 
 bool TaskDlgDatumParameters::accept()
 {
+    if (!parameter->isCompleted()) {
+        QMessageBox::warning(parameter, tr("Not enough references"), tr("Please select further references to complete this feature"));
+        return false;
+    }
+
     std::string name = DatumView->getObject()->getNameInDocument();
 
     try {
diff --git a/src/Mod/PartDesign/Gui/TaskDatumParameters.h b/src/Mod/PartDesign/Gui/TaskDatumParameters.h
index 9936172d4..c2ea01ba5 100644
--- a/src/Mod/PartDesign/Gui/TaskDatumParameters.h
+++ b/src/Mod/PartDesign/Gui/TaskDatumParameters.h
@@ -56,6 +56,7 @@ public:
     QString getReference(const int idx) const;
     double getValue1(void) const;
     bool   getCheck1(void) const;
+    const bool isCompleted() const { return completed; }
 
 private Q_SLOTS:
     void onValue1Changed(double);
@@ -85,6 +86,7 @@ private:
     ViewProviderDatum *DatumView;
 
     int refSelectionMode;
+    bool completed;
 
 };