diff --git a/ApplicationLibCode/ProjectDataModel/RimObservedDataCollection.cpp b/ApplicationLibCode/ProjectDataModel/RimObservedDataCollection.cpp
index 837e4d916a..2839a6523f 100644
--- a/ApplicationLibCode/ProjectDataModel/RimObservedDataCollection.cpp
+++ b/ApplicationLibCode/ProjectDataModel/RimObservedDataCollection.cpp
@@ -29,6 +29,7 @@
 #include "RimObservedEclipseUserData.h"
 #include "RimObservedFmuRftData.h"
 #include "RimObservedSummaryData.h"
+#include "RimProject.h"
 #include "RimSummaryObservedDataFile.h"
 
 #include "RiuPlotMainWindow.h"
@@ -154,6 +155,7 @@ RimObservedSummaryData*
         errorText->append( observedData->errorMessagesFromReader() );
     }
 
+    RimProject::current()->assignCaseIdToSummaryCase( observedData );
     updateNewObservedDataCreated( observedData );
 
     this->updateConnectedEditors();
@@ -221,6 +223,7 @@ RimObservedSummaryData*
         return nullptr;
     }
 
+    RimProject::current()->assignCaseIdToSummaryCase( observedData );
     updateNewObservedDataCreated( observedData );
 
     this->updateConnectedEditors();
diff --git a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp
index 41f405c1e2..d15472414d 100644
--- a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp
+++ b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp
@@ -2884,16 +2884,45 @@ void RimSummaryPlot::assignPlotAxis( RimSummaryCurve* destinationCurve )
         ALL_TO_LEFT,
         ALL_TO_RIGHT,
         ALTERNATING,
-        USE_MATCHING_UNIT
+        USE_MATCHING_UNIT,
+        USE_MATCHING_VECTOR
     };
 
-    RiaDefines::PlotAxis plotAxis = RiaDefines::PlotAxis::PLOT_AXIS_LEFT;
-
     auto strategy = AxisAssignmentStrategy::USE_MATCHING_UNIT;
-    if ( strategy == AxisAssignmentStrategy::USE_MATCHING_UNIT )
-    {
-        auto destinationUnit = destinationCurve->unitNameY();
 
+    auto destinationUnit = destinationCurve->unitNameY();
+    if ( destinationUnit.empty() ) strategy = AxisAssignmentStrategy::USE_MATCHING_VECTOR;
+
+    auto anyCurveWithUnitText = [this, destinationCurve] {
+        for ( auto c : summaryCurves() )
+        {
+            if ( c == destinationCurve ) continue;
+
+            if ( !c->unitNameY().empty() ) return true;
+        }
+
+        return false;
+    };
+
+    if ( !anyCurveWithUnitText() ) strategy = AxisAssignmentStrategy::USE_MATCHING_VECTOR;
+
+    if ( strategy == AxisAssignmentStrategy::USE_MATCHING_VECTOR )
+    {
+        // Special handling if curve unit is matching. Try to match on summary vector name to avoid creation of new axis
+
+        for ( auto c : summaryCurves() )
+        {
+            if ( c == destinationCurve ) continue;
+
+            if ( c->summaryAddressY().vectorName() == destinationCurve->summaryAddressY().vectorName() )
+            {
+                destinationCurve->setLeftOrRightAxisY( c->axisY() );
+                return;
+            }
+        }
+    }
+    else if ( strategy == AxisAssignmentStrategy::USE_MATCHING_UNIT )
+    {
         bool isLeftUsed  = false;
         bool isRightUsed = false;
 
@@ -2936,6 +2965,8 @@ void RimSummaryPlot::assignPlotAxis( RimSummaryCurve* destinationCurve )
         strategy = AxisAssignmentStrategy::ALTERNATING;
     }
 
+    RiaDefines::PlotAxis plotAxisType = RiaDefines::PlotAxis::PLOT_AXIS_LEFT;
+
     if ( strategy == AxisAssignmentStrategy::ALTERNATING )
     {
         size_t axisCountLeft  = 0;
@@ -2948,15 +2979,15 @@ void RimSummaryPlot::assignPlotAxis( RimSummaryCurve* destinationCurve )
                 axisCountRight++;
         }
 
-        if ( axisCountLeft > axisCountRight ) plotAxis = RiaDefines::PlotAxis::PLOT_AXIS_RIGHT;
+        if ( axisCountLeft > axisCountRight ) plotAxisType = RiaDefines::PlotAxis::PLOT_AXIS_RIGHT;
     }
     else if ( strategy == AxisAssignmentStrategy::ALL_TO_LEFT )
     {
-        plotAxis = RiaDefines::PlotAxis::PLOT_AXIS_LEFT;
+        plotAxisType = RiaDefines::PlotAxis::PLOT_AXIS_LEFT;
     }
     else if ( strategy == AxisAssignmentStrategy::ALL_TO_RIGHT )
     {
-        plotAxis = RiaDefines::PlotAxis::PLOT_AXIS_RIGHT;
+        plotAxisType = RiaDefines::PlotAxis::PLOT_AXIS_RIGHT;
     }
 
     RiuPlotAxis newPlotAxis = RiuPlotAxis::defaultLeft();
@@ -2966,7 +2997,7 @@ void RimSummaryPlot::assignPlotAxis( RimSummaryCurve* destinationCurve )
         if ( !destinationCurve->summaryAddressY().uiText().empty() )
             axisObjectName = QString::fromStdString( destinationCurve->summaryAddressY().uiText() );
 
-        newPlotAxis = plotWidget()->createNextPlotAxis( plotAxis );
+        newPlotAxis = plotWidget()->createNextPlotAxis( plotAxisType );
         addNewAxisProperties( newPlotAxis, axisObjectName );
     }