fix(widget): do not block logout on Linux desktop environments

Change closeEvent() to hideEvent() for handling main window closing.
Close event is no longer ignored, which prevented logging out from
various Linux desktop environments.

Closes #1485

src/widget/widget.cpp

@@ -568,12 +568,11 @@ void Widget::moveEvent(QMoveEvent *event)
     QWidget::moveEvent(event);
 }
 
-void Widget::closeEvent(QCloseEvent *event)
+void Widget::hideEvent(QHideEvent *event)
 {
     if (Settings::getInstance().getShowSystemTray() && Settings::getInstance().getCloseToTray())
     {
-        event->ignore();
-        this->hide();
+        QWidget::hideEvent(event);
     }
     else
     {
@@ -584,7 +583,7 @@ void Widget::closeEvent(QCloseEvent *event)
         }
         saveWindowGeometry();
         saveSplitterGeometry();
-        QWidget::closeEvent(event);
+        QWidget::hideEvent(event);
         qApp->quit();
     }
 }

src/widget/widget.h

@@ -161,7 +161,7 @@ public slots:
 protected:
     virtual bool eventFilter(QObject *obj, QEvent *event) final override;
     virtual bool event(QEvent * e) final override;
-    virtual void closeEvent(QCloseEvent *event) final override;
+    virtual void hideEvent(QHideEvent *event) final override;
     virtual void changeEvent(QEvent *event) final override;
     virtual void resizeEvent(QResizeEvent *event) final override;
     virtual void moveEvent(QMoveEvent *event) final override;