diff --git a/key.ui/src/main/java/de/uka/ilkd/key/gui/MainWindow.java b/key.ui/src/main/java/de/uka/ilkd/key/gui/MainWindow.java
index 9ca06df9927..4863623dce8 100644
--- a/key.ui/src/main/java/de/uka/ilkd/key/gui/MainWindow.java
+++ b/key.ui/src/main/java/de/uka/ilkd/key/gui/MainWindow.java
@@ -1225,7 +1225,7 @@ private synchronized void updateSequentView() {
         }
 
         Runnable sequentUpdater = () -> {
-            mainFrame.setContent(newSequentView);
+            mainFrame.setSequentView(newSequentView);
             // always does printSequent if on the event thread
             sequentViewSearchBar.setSequentView(newSequentView);
         };
@@ -1256,6 +1256,15 @@ public void scrollTo(int y) {
         mainFrame.scrollTo(y);
     }
 
+    /**
+     * Get the main frame for access to the sequent view
+     *
+     * @return the container for this main window.
+     */
+    public MainFrame getMainFrame() {
+        return mainFrame;
+    }
+
     void displayResults(String message) {
         LOGGER.debug("displaying results: {}", message);
         setStatusLine(message);
diff --git a/key.ui/src/main/java/de/uka/ilkd/key/gui/actions/HeatmapToggleAction.java b/key.ui/src/main/java/de/uka/ilkd/key/gui/actions/HeatmapToggleAction.java
index aa196ab72f0..762d119aa04 100644
--- a/key.ui/src/main/java/de/uka/ilkd/key/gui/actions/HeatmapToggleAction.java
+++ b/key.ui/src/main/java/de/uka/ilkd/key/gui/actions/HeatmapToggleAction.java
@@ -3,6 +3,7 @@
  * SPDX-License-Identifier: GPL-2.0-only */
 package de.uka.ilkd.key.gui.actions;
 
+import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.beans.PropertyChangeListener;
 import javax.swing.*;
@@ -11,6 +12,7 @@
 import de.uka.ilkd.key.core.KeYSelectionListener;
 import de.uka.ilkd.key.gui.MainWindow;
 import de.uka.ilkd.key.gui.fonticons.IconFactory;
+import de.uka.ilkd.key.gui.nodeviews.SequentView;
 import de.uka.ilkd.key.proof.Proof;
 import de.uka.ilkd.key.settings.ProofIndependentSettings;
 import de.uka.ilkd.key.settings.ViewSettings;
@@ -65,7 +67,10 @@ public void actionPerformed(ActionEvent e) {
         vs.setHeatmapOptions(!vs.isShowHeatmap(), vs.isHeatmapSF(), vs.isHeatmapNewest(),
             vs.getMaxAgeForHeatmap());
         // this updates the heatmap highlights
-        mainWindow.getCurrentGoalView().getHighlighter().removeAllHighlights();
-        mainWindow.getCurrentGoalView().printSequent();
+        SequentView sequentView = mainWindow.getMainFrame().getSequentView();
+        if (sequentView != null) {
+            sequentView.getHighlighter().removeAllHighlights();
+            sequentView.printSequent();
+        }
     }
 }
diff --git a/key.ui/src/main/java/de/uka/ilkd/key/gui/nodeviews/MainFrame.java b/key.ui/src/main/java/de/uka/ilkd/key/gui/nodeviews/MainFrame.java
index 5a8abd84bb9..e71e60db09a 100644
--- a/key.ui/src/main/java/de/uka/ilkd/key/gui/nodeviews/MainFrame.java
+++ b/key.ui/src/main/java/de/uka/ilkd/key/gui/nodeviews/MainFrame.java
@@ -26,15 +26,15 @@ public final class MainFrame extends JPanel {
     private static final long serialVersionUID = -2412537422601138379L;
 
     private final JScrollPane scrollPane = new JScrollPane();
-    private Component content;
+    private SequentView sequentView;
     private boolean showTacletInfo = false;
 
-    public Component setContent(Component component) {
-        Component oldContent = content;
-        content = component;
-        if (component instanceof SequentView sequentView) {
+    public void setSequentView(SequentView component) {
+        SequentView oldSequentView = sequentView;
+        sequentView = component;
+        if (component != null) {
             Point oldSequentViewPosition = scrollPane.getViewport().getViewPosition();
-            scrollPane.setViewportView(new SequentViewPanel(sequentView));
+            scrollPane.setViewportView(new SequentViewPanel(component));
             scrollPane.getViewport().setViewPosition(oldSequentViewPosition);
 
             setShowTacletInfo(showTacletInfo);
@@ -42,11 +42,10 @@ public Component setContent(Component component) {
             scrollPane.setViewportView(component);
         }
 
-        if (oldContent instanceof SequentView) {
-            ((SequentView) oldContent).removeUserSelectionHighlight();
+        if (oldSequentView != null) {
+            oldSequentView.removeUserSelectionHighlight();
         }
 
-        return oldContent;
     }
 
     public MainFrame(final MainWindow mainWindow, EmptySequent emptySequent) {
@@ -58,8 +57,8 @@ public MainFrame(final MainWindow mainWindow, EmptySequent emptySequent) {
 
             @Override
             public void mouseClicked(MouseEvent e) {
-                if (content != null) {
-                    for (MouseListener listener : content.getMouseListeners()) {
+                if (sequentView != null) {
+                    for (MouseListener listener : sequentView.getMouseListeners()) {
                         if (listener instanceof SequentViewInputListener) {
                             listener.mouseClicked(e);
                         }
@@ -72,8 +71,8 @@ public void mouseClicked(MouseEvent e) {
 
             @Override
             public void ancestorRemoved(AncestorEvent event) {
-                if (content instanceof SequentView) {
-                    ((SequentView) content).removeUserSelectionHighlight();
+                if (sequentView != null) {
+                    sequentView.removeUserSelectionHighlight();
                 }
             }
 
@@ -90,13 +89,13 @@ public void ancestorAdded(AncestorEvent event) {}
         getActionMap().put("copy", new CopyToClipboardAction(mainWindow));
         setLayout(new BorderLayout());
         add(scrollPane);
-        setContent(emptySequent);
+        setSequentView(emptySequent);
     }
 
     public void setShowTacletInfo(boolean showTacletInfo) {
         this.showTacletInfo = showTacletInfo;
 
-        if (content instanceof InnerNodeView view) {
+        if (sequentView instanceof InnerNodeView view) {
             view.tacletInfo.setVisible(this.showTacletInfo);
         }
     }
@@ -113,4 +112,8 @@ public boolean isShowTacletInfo() {
     public void scrollTo(int y) {
         scrollPane.getVerticalScrollBar().setValue(y);
     }
+
+    public SequentView getSequentView() {
+        return sequentView;
+    }
 }