diff --git a/src/private/Frame.cpp b/src/private/Frame.cpp
index 328f028c..6acfc4bf 100644
--- a/src/private/Frame.cpp
+++ b/src/private/Frame.cpp
@@ -199,7 +199,7 @@ FloatingWindow* Frame::detachTab(DockWidgetBase *dockWidget)
     return floatingWindow;
 }
 
-int Frame::indexOfDockWidget(DockWidgetBase *dw)
+int Frame::indexOfDockWidget(const DockWidgetBase *dw)
 {
     if (m_inCtor || m_inDtor) return -1;
 
diff --git a/src/private/Frame_p.h b/src/private/Frame_p.h
index b5c80e44..78e0eda7 100644
--- a/src/private/Frame_p.h
+++ b/src/private/Frame_p.h
@@ -84,7 +84,7 @@ public:
     FloatingWindow *detachTab(DockWidgetBase *);
 
     ///@brief returns the index of the specified dock widget
-    int indexOfDockWidget(DockWidgetBase *);
+    int indexOfDockWidget(const DockWidgetBase *);
 
     ///@brief returns the index of the current tab
     int currentIndex() const;
@@ -293,7 +293,7 @@ protected:
     QSize biggestDockWidgetMaxSize() const;
 
     virtual void removeWidget_impl(DockWidgetBase *) = 0;
-    virtual int indexOfDockWidget_impl(DockWidgetBase *) = 0;
+    virtual int indexOfDockWidget_impl(const DockWidgetBase *) = 0;
     virtual int currentIndex_impl() const = 0;
     virtual void setCurrentTabIndex_impl(int index) = 0;
     virtual void setCurrentDockWidget_impl(DockWidgetBase *) = 0;
diff --git a/src/private/TabWidget_p.h b/src/private/TabWidget_p.h
index bf9a0ffe..6e1946bd 100644
--- a/src/private/TabWidget_p.h
+++ b/src/private/TabWidget_p.h
@@ -109,7 +109,7 @@ public:
     /**
      * @brief Returns the index of the dock widget, or -1 if it doesn't exist
      */
-    virtual int indexOfDockWidget(DockWidgetBase *) const = 0;
+    virtual int indexOfDockWidget(const DockWidgetBase *) const = 0;
 
     /**
      * @brief Sets the current dock widget index
diff --git a/src/private/quick/FrameQuick.cpp b/src/private/quick/FrameQuick.cpp
index b98f8ddd..3a582da7 100644
--- a/src/private/quick/FrameQuick.cpp
+++ b/src/private/quick/FrameQuick.cpp
@@ -84,7 +84,7 @@ void FrameQuick::removeWidget_impl(DockWidgetBase *dw)
     disconnect(m_connections.take(dw));
 }
 
-int FrameQuick::indexOfDockWidget_impl(DockWidgetBase *dw)
+int FrameQuick::indexOfDockWidget_impl(const DockWidgetBase *dw)
 {
     return m_tabWidget->indexOfDockWidget(dw);
 }
diff --git a/src/private/quick/FrameQuick_p.h b/src/private/quick/FrameQuick_p.h
index 991d0e93..6677ff4c 100644
--- a/src/private/quick/FrameQuick_p.h
+++ b/src/private/quick/FrameQuick_p.h
@@ -49,7 +49,7 @@ public:
 
 protected:
     void removeWidget_impl(DockWidgetBase *) override;
-    int indexOfDockWidget_impl(DockWidgetBase *) override;
+    int indexOfDockWidget_impl(const DockWidgetBase *) override;
     int currentIndex_impl() const override;
     void setCurrentTabIndex_impl(int index) override;
     void setCurrentDockWidget_impl(DockWidgetBase *) override;
diff --git a/src/private/quick/TabWidgetQuick.cpp b/src/private/quick/TabWidgetQuick.cpp
index 66d9430e..23cd90cb 100644
--- a/src/private/quick/TabWidgetQuick.cpp
+++ b/src/private/quick/TabWidgetQuick.cpp
@@ -43,7 +43,7 @@ void TabWidgetQuick::removeDockWidget(DockWidgetBase *dw)
     m_dockWidgetModel->remove(dw);
 }
 
-int TabWidgetQuick::indexOfDockWidget(DockWidgetBase *dw) const
+int TabWidgetQuick::indexOfDockWidget(const DockWidgetBase *dw) const
 {
     return m_dockWidgetModel->indexOf(dw);
 }
@@ -186,9 +186,9 @@ void DockWidgetModel::remove(DockWidgetBase *dw)
     }
 }
 
-int DockWidgetModel::indexOf(DockWidgetBase *dw)
+int DockWidgetModel::indexOf(const DockWidgetBase *dw)
 {
-    return m_dockWidgets.indexOf(dw);
+    return m_dockWidgets.indexOf(const_cast<DockWidgetBase*>(dw));
 }
 
 bool DockWidgetModel::insert(DockWidgetBase *dw, int index)
diff --git a/src/private/quick/TabWidgetQuick_p.h b/src/private/quick/TabWidgetQuick_p.h
index 6c2a35e7..748565e9 100644
--- a/src/private/quick/TabWidgetQuick_p.h
+++ b/src/private/quick/TabWidgetQuick_p.h
@@ -46,7 +46,7 @@ public:
 
     int numDockWidgets() const override;
     void removeDockWidget(DockWidgetBase *) override;
-    int indexOfDockWidget(DockWidgetBase *) const override;
+    int indexOfDockWidget(const DockWidgetBase *) const override;
     DockWidgetModel *dockWidgetModel() const;
     DockWidgetBase *dockwidgetAt(int index) const override;
     int currentIndex() const override;
@@ -88,7 +88,7 @@ public:
     QVariant data(const QModelIndex &index, int role) const override;
     DockWidgetBase *dockWidgetAt(int index) const;
     void remove(DockWidgetBase *);
-    int indexOf(DockWidgetBase *);
+    int indexOf(const DockWidgetBase *);
     bool insert(DockWidgetBase *dw, int index);
     bool contains(DockWidgetBase *dw) const;
 protected:
diff --git a/src/private/widgets/FrameWidget.cpp b/src/private/widgets/FrameWidget.cpp
index 40410062..96df8f8c 100644
--- a/src/private/widgets/FrameWidget.cpp
+++ b/src/private/widgets/FrameWidget.cpp
@@ -101,7 +101,7 @@ QSize FrameWidget::maxSizeHint() const
     return waste + biggestDockWidgetMaxSize();
 }
 
-int FrameWidget::indexOfDockWidget_impl(DockWidgetBase *dw)
+int FrameWidget::indexOfDockWidget_impl(const DockWidgetBase *dw)
 {
     return m_tabWidget->indexOfDockWidget(dw);
 }
diff --git a/src/private/widgets/FrameWidget_p.h b/src/private/widgets/FrameWidget_p.h
index 1532826f..fe0f28c5 100644
--- a/src/private/widgets/FrameWidget_p.h
+++ b/src/private/widgets/FrameWidget_p.h
@@ -39,7 +39,7 @@ public:
 protected:
     void paintEvent(QPaintEvent *) override;
     QSize maxSizeHint() const override;
-    int indexOfDockWidget_impl(DockWidgetBase *) override;
+    int indexOfDockWidget_impl(const DockWidgetBase *) override;
     void setCurrentDockWidget_impl(DockWidgetBase *) override;
     int currentIndex_impl() const override;
     void insertDockWidget_impl(DockWidgetBase *, int index) override;
diff --git a/src/private/widgets/TabWidgetWidget.cpp b/src/private/widgets/TabWidgetWidget.cpp
index 32ed87d4..399a5bab 100644
--- a/src/private/widgets/TabWidgetWidget.cpp
+++ b/src/private/widgets/TabWidgetWidget.cpp
@@ -69,9 +69,9 @@ void TabWidgetWidget::removeDockWidget(DockWidgetBase *dw)
     removeTab(indexOf(dw));
 }
 
-int TabWidgetWidget::indexOfDockWidget(DockWidgetBase *dw) const
+int TabWidgetWidget::indexOfDockWidget(const DockWidgetBase *dw) const
 {
-    return indexOf(dw);
+    return indexOf(const_cast<DockWidgetBase*>(dw));
 }
 
 void TabWidgetWidget::mouseDoubleClickEvent(QMouseEvent *ev)
diff --git a/src/private/widgets/TabWidgetWidget_p.h b/src/private/widgets/TabWidgetWidget_p.h
index 2502e59e..d9e7e34d 100644
--- a/src/private/widgets/TabWidgetWidget_p.h
+++ b/src/private/widgets/TabWidgetWidget_p.h
@@ -40,7 +40,7 @@ public:
 
     int numDockWidgets() const override;
     void removeDockWidget(DockWidgetBase *) override;
-    int indexOfDockWidget(DockWidgetBase *) const override;
+    int indexOfDockWidget(const DockWidgetBase *) const override;
 
 Q_SIGNALS:
     void currentTabChanged(int index) override;