Don't set all top bar buttons to checkable

Some of them can only be clicked (e.g. End Turn).

See longturn#940.

client/gui-qt/page_game.cpp

@@ -84,19 +84,23 @@ pageGame::pageGame(QWidget *parent)
   sw_cities->setIcon(fcIcons::instance()->getIcon(QStringLiteral("cities")));
   sw_cities->setWheelUp(center_next_enemy_city);
   sw_cities->setWheelDown(center_next_player_city);
+  sw_cities->setCheckable(true);
   sw_diplo = new top_bar_widget(
       _("Nations"), QStringLiteral("PLR"), popup_players_dialog);
   sw_diplo->setIcon(fcIcons::instance()->getIcon(QStringLiteral("nations")));
   sw_diplo->setWheelUp(center_next_player_capital);
   sw_diplo->setWheelDown(key_center_capital);
+  sw_diplo->setCheckable(true);
   sw_science = new top_bar_widget(
       _("Research"), QStringLiteral("SCI"), top_bar_left_click_science);
   sw_science->setIcon(
       fcIcons::instance()->getIcon(QStringLiteral("research")));
+  sw_science->setCheckable(true);
   sw_economy = new top_bar_widget(
       _("Economy"), QStringLiteral("ECO"), economy_report_dialog_popup);
   sw_economy->setIcon(
       fcIcons::instance()->getIcon(QStringLiteral("economy")));
+  sw_economy->setCheckable(true);
   sw_endturn = new top_bar_widget(
       _("Turn Done"), QLatin1String(""), top_bar_finish_turn);
   sw_endturn->setIcon(

client/gui-qt/top_bar.cpp

@@ -67,7 +67,6 @@ top_bar_widget::top_bar_widget(const QString &label, const QString &pg,
   setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
   setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
   setContextMenuPolicy(Qt::CustomContextMenu);
-  setCheckable(true);
 
   timer = new QTimer;
   timer->setSingleShot(false);