diff --git a/libtaskmanager/abstracttasksmodel.h b/libtaskmanager/abstracttasksmodel.h
--- a/libtaskmanager/abstracttasksmodel.h
+++ b/libtaskmanager/abstracttasksmodel.h
@@ -90,7 +90,7 @@
 
     QHash<int, QByteArray> roleNames() const override;
 
-    virtual QModelIndex	index(int row, int column = 0, const QModelIndex &parent = QModelIndex()) const;
+    virtual QModelIndex	index(int row, int column = 0, const QModelIndex &parent = QModelIndex()) const override;
 
     /**
      * Request activation of the task at the given index. Derived classes are
@@ -101,7 +101,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestActivate(const QModelIndex &index);
+    virtual void requestActivate(const QModelIndex &index) override;
 
     /**
      * Request an additional instance of the application backing the task
@@ -111,16 +111,16 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestNewInstance(const QModelIndex &index);
+    virtual void requestNewInstance(const QModelIndex &index) override;
 
     /**
      * Request the task at the given index be closed.
      *
      * This base implementation does nothing.
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestClose(const QModelIndex &index);
+    virtual void requestClose(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive move for the task at the given index.
@@ -132,7 +132,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestMove(const QModelIndex &index);
+    virtual void requestMove(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive resize for the task at the given index.
@@ -144,7 +144,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestResize(const QModelIndex &index);
+    virtual void requestResize(const QModelIndex &index) override;
 
     /**
      * Request toggling the minimized state of the task at the given index.
@@ -156,7 +156,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestToggleMinimized(const QModelIndex &index);
+    virtual void requestToggleMinimized(const QModelIndex &index) override;
 
     /**
      * Request toggling the maximized state of the task at the given index.
@@ -168,7 +168,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestToggleMaximized(const QModelIndex &index);
+    virtual void requestToggleMaximized(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-above state of the task at the given index.
@@ -180,7 +180,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestToggleKeepAbove(const QModelIndex &index);
+    virtual void requestToggleKeepAbove(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-below state of the task at the given index.
@@ -192,7 +192,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestToggleKeepBelow(const QModelIndex &index);
+    virtual void requestToggleKeepBelow(const QModelIndex &index) override;
 
     /**
      * Request toggling the fullscreen state of the task at the given index.
@@ -204,7 +204,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestToggleFullScreen(const QModelIndex &index);
+    virtual void requestToggleFullScreen(const QModelIndex &index) override;
 
     /**
      * Request toggling the shaded state of the task at the given index.
@@ -216,7 +216,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    virtual void requestToggleShaded(const QModelIndex &index);
+    virtual void requestToggleShaded(const QModelIndex &index) override;
 
     /**
      * Request moving the task at the given index to the specified virtual
@@ -230,7 +230,7 @@
      * @param index An index in this tasks model.
      * @param desktop A virtual desktop number.
      **/
-    virtual void requestVirtualDesktop(const QModelIndex &index, qint32 desktop);
+    virtual void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
      * Request informing the window manager of new geometry for a visual
@@ -246,7 +246,7 @@
      * reject invalid objects.
      **/
     virtual void requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry,
-        QObject *delegate = nullptr);
+        QObject *delegate = nullptr) override;
 };
 
 }
diff --git a/libtaskmanager/flattentaskgroupsproxymodel.h b/libtaskmanager/flattentaskgroupsproxymodel.h
--- a/libtaskmanager/flattentaskgroupsproxymodel.h
+++ b/libtaskmanager/flattentaskgroupsproxymodel.h
@@ -58,22 +58,22 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestActivate(const QModelIndex &index);
+    void requestActivate(const QModelIndex &index) override;
 
     /**
      * Request an additional instance of the application backing the task
      * at the given index.
      *
      * @param index An index in this tasks model.
      **/
-    void requestNewInstance(const QModelIndex &index);
+    void requestNewInstance(const QModelIndex &index) override;
 
     /**
      * Request the task at the given index be closed.
      *
      * @param index An index in this tasks model.
      **/
-    void requestClose(const QModelIndex &index);
+    void requestClose(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive move for the task at the given index.
@@ -83,7 +83,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestMove(const QModelIndex &index);
+    void requestMove(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive resize for the task at the given index.
@@ -93,7 +93,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestResize(const QModelIndex &index);
+    void requestResize(const QModelIndex &index) override;
 
     /**
      * Request toggling the minimized state of the task at the given index.
@@ -103,7 +103,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleMinimized(const QModelIndex &index);
+    void requestToggleMinimized(const QModelIndex &index) override;
 
     /**
      * Request toggling the maximized state of the task at the given index.
@@ -113,7 +113,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleMaximized(const QModelIndex &index);
+    void requestToggleMaximized(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-above state of the task at the given index.
@@ -123,7 +123,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleKeepAbove(const QModelIndex &index);
+    void requestToggleKeepAbove(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-below state of the task at the given index.
@@ -133,7 +133,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleKeepBelow(const QModelIndex &index);
+    void requestToggleKeepBelow(const QModelIndex &index) override;
 
     /**
      * Request toggling the fullscreen state of the task at the given index.
@@ -143,7 +143,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleFullScreen(const QModelIndex &index);
+    void requestToggleFullScreen(const QModelIndex &index) override;
 
     /**
      * Request toggling the shaded state of the task at the given index.
@@ -153,7 +153,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleShaded(const QModelIndex &index);
+    void requestToggleShaded(const QModelIndex &index) override;
 
     /**
      * Request moving the task at the given index to the specified virtual
@@ -165,7 +165,7 @@
      * @param index An index in this tasks model.
      * @param desktop A virtual desktop number.
      **/
-    void requestVirtualDesktop(const QModelIndex &index, qint32 desktop);
+    void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
      * Request informing the window manager of new geometry for a visual
@@ -179,7 +179,7 @@
      * reject invalid objects.
      **/
     void requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry,
-        QObject *delegate = nullptr);
+        QObject *delegate = nullptr) override;
 
 private:
     class Private;
diff --git a/libtaskmanager/taskfilterproxymodel.h b/libtaskmanager/taskfilterproxymodel.h
--- a/libtaskmanager/taskfilterproxymodel.h
+++ b/libtaskmanager/taskfilterproxymodel.h
@@ -215,22 +215,22 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestActivate(const QModelIndex &index);
+    void requestActivate(const QModelIndex &index) override;
 
     /**
      * Request an additional instance of the application backing the task
      * at the given index.
      *
      * @param index An index in this tasks model.
      **/
-    void requestNewInstance(const QModelIndex &index);
+    void requestNewInstance(const QModelIndex &index) override;
 
     /**
      * Request the task at the given index be closed.
      *
      * @param index An index in this tasks model.
      **/
-    void requestClose(const QModelIndex &index);
+    void requestClose(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive move for the task at the given index.
@@ -240,7 +240,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestMove(const QModelIndex &index);
+    void requestMove(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive resize for the task at the given index.
@@ -250,7 +250,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestResize(const QModelIndex &index);
+    void requestResize(const QModelIndex &index) override;
 
     /**
      * Request toggling the minimized state of the task at the given index.
@@ -260,7 +260,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleMinimized(const QModelIndex &index);
+    void requestToggleMinimized(const QModelIndex &index) override;
 
     /**
      * Request toggling the maximized state of the task at the given index.
@@ -270,7 +270,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleMaximized(const QModelIndex &index);
+    void requestToggleMaximized(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-above state of the task at the given index.
@@ -280,7 +280,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleKeepAbove(const QModelIndex &index);
+    void requestToggleKeepAbove(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-below state of the task at the given index.
@@ -290,7 +290,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleKeepBelow(const QModelIndex &index);
+    void requestToggleKeepBelow(const QModelIndex &index) override;
 
     /**
      * Request toggling the fullscreen state of the task at the given index.
@@ -300,7 +300,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleFullScreen(const QModelIndex &index);
+    void requestToggleFullScreen(const QModelIndex &index) override;
 
     /**
      * Request toggling the shaded state of the task at the given index.
@@ -310,7 +310,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleShaded(const QModelIndex &index);
+    void requestToggleShaded(const QModelIndex &index) override;
 
     /**
      * Request moving the task at the given index to the specified virtual
@@ -322,7 +322,7 @@
      * @param index An index in this tasks model.
      * @param desktop A virtual desktop number.
      **/
-    void requestVirtualDesktop(const QModelIndex &index, qint32 desktop);
+    void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
      * Request informing the window manager of new geometry for a visual
@@ -336,7 +336,7 @@
      * reject invalid objects.
      **/
     void requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry,
-        QObject *delegate = nullptr);
+        QObject *delegate = nullptr) override;
 
 Q_SIGNALS:
     void virtualDesktopChanged() const;
@@ -348,7 +348,7 @@
     void filterNotMinimizedChanged() const;
 
 protected:
-    bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const;
+    bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;
 
 private:
     class Private;
diff --git a/libtaskmanager/taskgroupingproxymodel.h b/libtaskmanager/taskgroupingproxymodel.h
--- a/libtaskmanager/taskgroupingproxymodel.h
+++ b/libtaskmanager/taskgroupingproxymodel.h
@@ -201,22 +201,22 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestActivate(const QModelIndex &index);
+    void requestActivate(const QModelIndex &index) override;
 
     /**
      * Request an additional instance of the application backing the task
      * at the given index.
      *
      * @param index An index in this tasks model.
      **/
-    void requestNewInstance(const QModelIndex &index);
+    void requestNewInstance(const QModelIndex &index) override;
 
     /**
      * Request the task at the given index be closed.
      *
      * @param index An index in this tasks model.
      **/
-    void requestClose(const QModelIndex &index);
+    void requestClose(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive move for the task at the given index.
@@ -228,7 +228,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestMove(const QModelIndex &index);
+    void requestMove(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive resize for the task at the given index.
@@ -238,7 +238,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestResize(const QModelIndex &index);
+    void requestResize(const QModelIndex &index) override;
 
     /**
      * Request toggling the minimized state of the task at the given index.
@@ -250,7 +250,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleMinimized(const QModelIndex &index);
+    void requestToggleMinimized(const QModelIndex &index) override;
 
     /**
      * Request toggling the maximized state of the task at the given index.
@@ -260,7 +260,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleMaximized(const QModelIndex &index);
+    void requestToggleMaximized(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-above state of the task at the given index.
@@ -270,7 +270,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleKeepAbove(const QModelIndex &index);
+    void requestToggleKeepAbove(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-below state of the task at the given index.
@@ -280,7 +280,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleKeepBelow(const QModelIndex &index);
+    void requestToggleKeepBelow(const QModelIndex &index) override;
 
     /**
      * Request toggling the fullscreen state of the task at the given index.
@@ -292,7 +292,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleFullScreen(const QModelIndex &index);
+    void requestToggleFullScreen(const QModelIndex &index) override;
 
     /**
      * Request toggling the shaded state of the task at the given index.
@@ -302,7 +302,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    void requestToggleShaded(const QModelIndex &index);
+    void requestToggleShaded(const QModelIndex &index) override;
 
     /**
      * Request moving the task at the given index to the specified virtual
@@ -314,7 +314,7 @@
      * @param index An index in this tasks model.
      * @param desktop A virtual desktop number.
      **/
-    void requestVirtualDesktop(const QModelIndex &index, qint32 desktop);
+    void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
      * Request informing the window manager of new geometry for a visual
@@ -332,7 +332,7 @@
      * reject invalid objects.
      **/
     void requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry,
-        QObject *delegate = nullptr);
+        QObject *delegate = nullptr) override;
 
     /**
      * Request toggling whether the task at the given index, along with any
diff --git a/libtaskmanager/tasksmodel.h b/libtaskmanager/tasksmodel.h
--- a/libtaskmanager/tasksmodel.h
+++ b/libtaskmanager/tasksmodel.h
@@ -108,7 +108,7 @@
 
     QHash<int, QByteArray> roleNames() const override;
 
-    Q_INVOKABLE int rowCount(const QModelIndex &parent = QModelIndex()) const; // Invokable.
+    Q_INVOKABLE int rowCount(const QModelIndex &parent = QModelIndex()) const override; // Invokable.
 
     /**
      * The number of launcher tasks in the tast list.
@@ -513,22 +513,22 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestActivate(const QModelIndex &index);
+    Q_INVOKABLE void requestActivate(const QModelIndex &index) override;
 
     /**
      * Request an additional instance of the application backing the task
      * at the given index.
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestNewInstance(const QModelIndex &index);
+    Q_INVOKABLE void requestNewInstance(const QModelIndex &index) override;
 
     /**
      * Request the task at the given index be closed.
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestClose(const QModelIndex &index);
+    Q_INVOKABLE void requestClose(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive move for the task at the given index.
@@ -538,7 +538,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestMove(const QModelIndex &index);
+    Q_INVOKABLE void requestMove(const QModelIndex &index) override;
 
     /**
      * Request starting an interactive resize for the task at the given index.
@@ -548,7 +548,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestResize(const QModelIndex &index);
+    Q_INVOKABLE void requestResize(const QModelIndex &index) override;
 
     /**
      * Request toggling the minimized state of the task at the given index.
@@ -558,7 +558,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestToggleMinimized(const QModelIndex &index);
+    Q_INVOKABLE void requestToggleMinimized(const QModelIndex &index) override;
 
     /**
      * Request toggling the maximized state of the task at the given index.
@@ -568,7 +568,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestToggleMaximized(const QModelIndex &index);
+    Q_INVOKABLE void requestToggleMaximized(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-above state of the task at the given index.
@@ -578,7 +578,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestToggleKeepAbove(const QModelIndex &index);
+    Q_INVOKABLE void requestToggleKeepAbove(const QModelIndex &index) override;
 
     /**
      * Request toggling the keep-below state of the task at the given index.
@@ -588,7 +588,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestToggleKeepBelow(const QModelIndex &index);
+    Q_INVOKABLE void requestToggleKeepBelow(const QModelIndex &index) override;
 
     /**
      * Request toggling the fullscreen state of the task at the given index.
@@ -598,7 +598,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestToggleFullScreen(const QModelIndex &index);
+    Q_INVOKABLE void requestToggleFullScreen(const QModelIndex &index) override;
 
     /**
      * Request toggling the shaded state of the task at the given index.
@@ -608,7 +608,7 @@
      *
      * @param index An index in this tasks model.
      **/
-    Q_INVOKABLE void requestToggleShaded(const QModelIndex &index);
+    Q_INVOKABLE void requestToggleShaded(const QModelIndex &index) override;
 
     /**
      * Request moving the task at the given index to the specified virtual
@@ -620,7 +620,7 @@
      * @param index An index in this tasks model.
      * @param desktop A virtual desktop number.
      **/
-    Q_INVOKABLE void requestVirtualDesktop(const QModelIndex &index, qint32 desktop);
+    Q_INVOKABLE void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
      * Request informing the window manager of new geometry for a visual
@@ -638,7 +638,7 @@
      * reject invalid objects.
      **/
     Q_INVOKABLE void requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry,
-        QObject *delegate = nullptr);
+        QObject *delegate = nullptr) override;
 
     /**
      * Request toggling whether the task at the given index, along with any
@@ -727,8 +727,8 @@
     void groupingLauncherUrlBlacklistChanged() const;
 
 protected:
-    bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const;
-    bool lessThan(const QModelIndex &left, const QModelIndex &right) const;
+    bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;
+    bool lessThan(const QModelIndex &left, const QModelIndex &right) const override;
 
 private:
     Q_INVOKABLE void updateLauncherCount();