diff --git a/src/DatasetsAction.cpp b/src/DatasetsAction.cpp
index e31ce00..cbec33a 100644
--- a/src/DatasetsAction.cpp
+++ b/src/DatasetsAction.cpp
@@ -172,17 +172,10 @@ void DatasetsAction::setupPointSizeDatasetPickerAction(ScatterplotPlugin* scatte
     auto& pointSizeAction       = pointPlotAction.getSizeAction();
 
     _pointSizeDatasetPickerAction.setFilterFunction([this, scatterplotPlugin](mv::Dataset<DatasetImpl> dataset) -> bool {
-        if (dataset->getDataType() != PointType)
+        if (!scatterplotPlugin->getPositionDataset().isValid())
             return false;
 
-        const auto positionDataset = scatterplotPlugin->getPositionDataset();
-
-        if (!positionDataset.isValid())
-            return false;
-
-        const mv::Dataset<Points> candidatePoints(dataset);
-
-        if (candidatePoints->getNumPoints() != positionDataset->getNumPoints())
+    	if (dataset->getDataType() != PointType)
             return false;
 
         return true;
@@ -219,19 +212,12 @@ void DatasetsAction::setupPointOpacityDatasetPickerAction(ScatterplotPlugin* sca
     auto& pointOpacityAction    = pointPlotAction.getOpacityAction();
 
     _pointOpacityDatasetPickerAction.setFilterFunction([this, scatterplotPlugin](mv::Dataset<DatasetImpl> dataset) -> bool {
-        if (dataset->getDataType() != PointType)
-            return false;
-        
-        const auto positionDataset = scatterplotPlugin->getPositionDataset();
-
-        if (!positionDataset.isValid())
+        if (!scatterplotPlugin->getPositionDataset().isValid())
             return false;
 
-        const mv::Dataset<Points> candidatePoints(dataset);
-
-        if (candidatePoints->getNumPoints() != positionDataset->getNumPoints())
+    	if (dataset->getDataType() != PointType)
             return false;
-
+        
         return true;
     });
 
diff --git a/src/ScalarAction.cpp b/src/ScalarAction.cpp
index f151703..1c8d2da 100644
--- a/src/ScalarAction.cpp
+++ b/src/ScalarAction.cpp
@@ -18,7 +18,25 @@ ScalarAction::ScalarAction(QObject* parent, const QString& title, const float& m
     addAction(&_sourceAction);
 
     connect(&_sourceAction.getPickerAction(), &OptionAction::currentIndexChanged, this, [this](const std::uint32_t& currentIndex) {
-        emit sourceSelectionChanged(currentIndex);
+        bool emitSourceSelectionChanged = true;
+
+        if (currentIndex >= ScalarSourceModel::DefaultRow::DatasetStart) {
+            if (auto scatterplotPlugin = dynamic_cast<ScatterplotPlugin*>(findPluginAncestor())) {
+                auto positionDataset            = scatterplotPlugin->getPositionDataset();
+                auto scalarSourcePointsDataset  = Dataset<Points>(getCurrentDataset());
+                const auto numScalars           = scalarSourcePointsDataset->getNumPoints();
+                const auto numPositions         = positionDataset->getNumPoints();
+
+                if (numScalars != numPositions) {
+                    emitSourceSelectionChanged = false;
+
+                    scatterplotPlugin->addNotification(QString("The number of points in the scalar source dataset does not match the number of points in the position dataset. (numPositions=%1, numScalars:%2)").arg(QString::number(numPositions), QString::number(numScalars)));
+                }
+            }
+        }
+
+        if (emitSourceSelectionChanged)
+            emit sourceSelectionChanged(currentIndex);
     });
 
     connect(&_magnitudeAction, &DecimalAction::valueChanged, this, [this](const float& value) {
diff --git a/src/ScalarSourceAction.h b/src/ScalarSourceAction.h
index 5387c31..c4e808a 100644
--- a/src/ScalarSourceAction.h
+++ b/src/ScalarSourceAction.h
@@ -54,7 +54,7 @@ class ScalarSourceAction : public GroupAction
 
     /**
      * Load widget action from variant map
-     * @param Variant map representation of the widget action
+     * @param variantMap Variant map representation of the widget action
      */
     void fromVariantMap(const QVariantMap& variantMap) override;