fix(widget): do not block logout on Linux desktop environments v2

Revert commit 191fc15 to use closeEvent()
but without QEvent::ignore() which blocked logout on various Linux desktops,
and without redundant hide(). Previous fix with hideEvent() produced
regressions because hide() is used in various places, which produced closing
behavior.

Since qApp->setQuitOnLastWindowClosed(false) is used, and
Qt::WA_DeleteOnClose is *NOT* used, default closeEvent() handling is enough
for implementing close-to-systray feature.

Improves fix for #1485 and closes #3699

src/widget/widget.cpp

@@ -568,11 +568,11 @@ void Widget::moveEvent(QMoveEvent *event)
     QWidget::moveEvent(event);
 }
 
-void Widget::hideEvent(QHideEvent *event)
+void Widget::closeEvent(QCloseEvent *event)
 {
     if (Settings::getInstance().getShowSystemTray() && Settings::getInstance().getCloseToTray())
     {
-        QWidget::hideEvent(event);
+        QWidget::closeEvent(event);
     }
     else
     {
@@ -583,7 +583,7 @@ void Widget::hideEvent(QHideEvent *event)
         }
         saveWindowGeometry();
         saveSplitterGeometry();
-        QWidget::hideEvent(event);
+        QWidget::closeEvent(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 hideEvent(QHideEvent *event) final override;
+    virtual void closeEvent(QCloseEvent *event) final override;
     virtual void changeEvent(QEvent *event) final override;
     virtual void resizeEvent(QResizeEvent *event) final override;
     virtual void moveEvent(QMoveEvent *event) final override;