diff --git a/src/QImageViewer.cpp b/src/QImageViewer.cpp
index 9321d8b..44106e4 100644
--- a/src/QImageViewer.cpp
+++ b/src/QImageViewer.cpp
@@ -19,6 +19,8 @@
 
 QImageViewer::QImageViewer (QWidget* parent) : QWidget(parent) {
 
+    setFocusPolicy(Qt::StrongFocus); // So the widget can take focus and receive the +/-/ESC zoom keys.
+
     _zoomFactor = 1.0;
 
     // Setup the widgets
@@ -174,7 +176,7 @@ void QImageViewer::keyPressEvent (QKeyEvent* event) {
     }
 }
 
-void QImageViewer::enterEvent (QEvent* event) {
+void QImageViewer::enterEvent (QEnterEvent* event) {
 
     Q_UNUSED(event);
 
diff --git a/src/QImageViewer.h b/src/QImageViewer.h
index 82d43a3..197cf01 100644
--- a/src/QImageViewer.h
+++ b/src/QImageViewer.h
@@ -38,8 +38,8 @@ class QImageViewer : public QWidget {
 
     protected slots:
         void                    keyPressEvent           (QKeyEvent* event);
-        void                    enterEvent              (QEvent*    event);
-        void                    leaveEvent              (QEvent*    event);
+        void                    enterEvent              (QEnterEvent* event) override;
+        void                    leaveEvent              (QEvent*    event) override;
 
     private:
         QImage                  _image;