https://sourceforge.net/p/qmmp-dev/tickets/1185/
https://sourceforge.net/p/qmmp-dev/code/12150/

--- qmmp-2.2.3/src/plugins/Visual/projectm/projectmplugin.cpp
+++ qmmp-2.2.3/src/plugins/Visual/projectm/projectmplugin.cpp
@@ -59,8 +59,13 @@
     layout->setContentsMargins(0,0,0,0);
     setLayout(layout);
     addActions(m_projectMWidget->actions());
+#ifdef PROJECTM_4
+    connect(m_projectMWidget, &ProjectM4Widget::showMenuToggled, listWidget, &QListWidget::setVisible);
+    connect(m_projectMWidget, &ProjectM4Widget::fullscreenToggled, this, &ProjectMPlugin::setFullScreen);
+#else
     connect(m_projectMWidget, &ProjectMWidget::showMenuToggled, listWidget, &QListWidget::setVisible);
     connect(m_projectMWidget, &ProjectMWidget::fullscreenToggled, this, &ProjectMPlugin::setFullScreen);
+#endif
     listWidget->hide();
     resize(600,400);
     QSettings settings;