Give focus to AutomationEditor when the window gets the foucs (#5170)

This will make shortcuts work on opening the editor.

include/AutomationEditor.h

@@ -297,6 +297,9 @@ public slots:
 signals:
 	void currentPatternChanged();
 
+protected:
+	virtual void focusInEvent(QFocusEvent * event);
+
 protected slots:
 	void play();
 	void stop();

src/gui/editors/AutomationEditor.cpp

@@ -198,6 +198,8 @@ AutomationEditor::AutomationEditor() :
 	setCurrentPattern( NULL );
 
 	setMouseTracking( true );
+	setFocusPolicy( Qt::StrongFocus );
+	setFocus();
 }
 
 
@@ -2516,6 +2518,11 @@ void AutomationEditorWindow::clearCurrentPattern()
 	setCurrentPattern(nullptr);
 }
 
+void AutomationEditorWindow::focusInEvent(QFocusEvent * event)
+{
+	m_editor->setFocus( event->reason() );
+}
+
 void AutomationEditorWindow::play()
 {
 	m_editor->play();