Ensure small icons in monitor toolbar on Windows

src/monitor/monitor.cpp

@@ -199,6 +199,9 @@ Monitor::Monitor(Kdenlive::MonitorId id, MonitorManager *manager, QWidget *paren
 
     // Tool bar buttons
     m_toolbar = new QToolBar(this);
+    int size = style()->pixelMetric(QStyle::PM_SmallIconSize);
+    QSize iconSize(size, size);
+    m_toolbar->setIconSize(iconSize);
     QWidget *sp1 = new QWidget(this);
     sp1->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Preferred);
     m_toolbar->addWidget(sp1);