diff --git a/LocalizationService.cpp b/LocalizationService.cpp
index da70a00..7d96957 100644
--- a/LocalizationService.cpp
+++ b/LocalizationService.cpp
@@ -6,6 +6,8 @@
 #include <vtkImageData.h>
 #include <vtkMarchingCubes.h>
 #include <vtkNew.h>
+#include <vtkPointData.h>
+#include <vtkPointDataToCellData.h>
 #include <vtkPoints.h>
 #include <vtkPolyData.h>
 #include <vtkPolyDataConnectivityFilter.h>
@@ -30,7 +32,7 @@ struct Surf
     Point3d centroid;
 };
 
-static Point3d centroidFromPoints(const vtkPoints* pts)
+static Point3d centroidFromPoints(vtkPoints* pts)
 {
     Point3d c;
     if (!pts) return c;
@@ -41,6 +43,7 @@ static Point3d centroidFromPoints(const vtkPoints* pts)
     double p[3];
     for (vtkIdType i = 0; i < n; ++i)
     {
+        // vtkPoints::GetPoint is non-const in VTK 9.x, so keep pts non-const here.
         pts->GetPoint(i, p);
         sx += p[0];
         sy += p[1];
diff --git a/gRen.h b/gRen.h
index 0dd7e77..173686d 100644
--- a/gRen.h
+++ b/gRen.h
@@ -34,6 +34,16 @@
 
 #include <vtkSmartVolumeMapper.h>
 
+// Types used as members / inlined code below
+#include <vtkCamera.h>
+#include <vtkColorTransferFunction.h>
+#include <vtkFieldData.h>
+#include <vtkPiecewiseFunction.h>
+#include <vtkPointData.h>
+#include <vtkStringArray.h>
+#include <vtkTextProperty.h>
+#include <vtkVolumeProperty.h>
+
 
 #include <vtkPolyDataMapper.h>
 #include <vtkActor.h>
diff --git a/mainw.cpp b/mainw.cpp
index 0dd45c2..bff9f18 100644
--- a/mainw.cpp
+++ b/mainw.cpp
@@ -1091,6 +1091,7 @@ void MainWindow::onLocalizationError(const QString& message)
 {
     qWarning() << "Localization error:" << message;
     // Re-enable UI bits if needed
-    Ui->pb_localize->setEnabled(true);
-    Ui->pb_localize_abort->setEnabled(false);
+    // UI uses generic button names from the legacy .ui
+    Ui->pushButton_3->setEnabled(true);  // "Localize" / start
+    Ui->pushButton_4->setEnabled(false); // abort
 }