Remove "hover" flag in top bar widgets

It was used for a tiny graphical tweak of little importance.

See longturn#940.

client/gui-qt/top_bar.cpp

@@ -60,8 +60,8 @@ void reduce_mod(int &mod, int &val)
 top_bar_widget::top_bar_widget(const QString &label, const QString &pg,
                                pfcn_bool func, standards type)
     : QToolButton(), blink(false), keep_blinking(false), standard(type),
-      page(pg), hover(false), right_click(nullptr), wheel_down(nullptr),
-      wheel_up(nullptr), left_click(func)
+      page(pg), right_click(nullptr), wheel_down(nullptr), wheel_up(nullptr),
+      left_click(func)
 {
   setText(label);
   setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
@@ -190,42 +190,6 @@ void top_bar_widget::paintEvent(QPaintEvent *event)
   QToolButton::paintEvent(event);
 }
 
-/**
-   Mouse entered on widget area
- */
-void top_bar_widget::enterEvent(QEvent *event)
-{
-  if (!hover) {
-    hover = true;
-    QWidget::enterEvent(event);
-    update();
-  }
-}
-
-/**
-   Mouse left widget area
- */
-void top_bar_widget::leaveEvent(QEvent *event)
-{
-  if (hover) {
-    hover = false;
-    QWidget::leaveEvent(event);
-    update();
-  }
-}
-
-/**
-   Context menu requested
- */
-void top_bar_widget::contextMenuEvent(QContextMenuEvent *event)
-{
-  if (hover) {
-    hover = false;
-    QWidget::contextMenuEvent(event);
-    update();
-  }
-}
-
 /**
    Sets callback for mouse left click
  */

client/gui-qt/top_bar.h

@@ -62,15 +62,11 @@ public slots:
   void someSlot();
 
 protected:
-  void contextMenuEvent(QContextMenuEvent *event) override;
-  void enterEvent(QEvent *event) override;
-  void leaveEvent(QEvent *event) override;
   void mousePressEvent(QMouseEvent *event) override;
   void paintEvent(QPaintEvent *event) override;
   void wheelEvent(QWheelEvent *event) override;
 
 private:
-  bool hover;
   pfcn right_click;
   pfcn wheel_down;
   pfcn wheel_up;