diff --git a/src/gui/MainWindow.cpp b/src/gui/MainWindow.cpp
index c8e79372..b9be40b5 100644
--- a/src/gui/MainWindow.cpp
+++ b/src/gui/MainWindow.cpp
@@ -39,8 +39,12 @@
 
 namespace mmp {
 
+MainWindow* MainWindow::_instance = nullptr;
+
 MainWindow::MainWindow()
 {
+  _instance = this;
+
   // Create model.
 #if QT_VERSION >= 0x050500
   QMessageLogger(__FILE__, __LINE__, nullptr).info() << "Video support: " <<
@@ -3617,11 +3621,10 @@ QString MainWindow::locateMediaFile(const QString &uri, bool isImage)
 }
 
 MainWindow* MainWindow::window() {
-  static MainWindow* instance = nullptr;
-  if (!instance) {
-    instance = new MainWindow;
+  if (!_instance) {
+    new MainWindow; // sets _instance first thing
   }
-  return instance;
+  return _instance;
 }
 
 void MainWindow::updateCanvases()
diff --git a/src/gui/MainWindow.h b/src/gui/MainWindow.h
index fb17d9ca..80000770 100644
--- a/src/gui/MainWindow.h
+++ b/src/gui/MainWindow.h
@@ -363,6 +363,15 @@ public slots:
 
   static MainWindow* window();
 
+private:
+  // The singleton, published as soon as construction starts so that anything
+  // triggered from inside the constructor (e.g. restoring the output window in
+  // fullscreen repaints OutputGLCanvas, which asks for the main window) gets
+  // this instance instead of constructing a second one recursively.
+  static MainWindow* _instance;
+
+public:
+
   // Returns a short version of filename.
   static QString strippedName(const QString &fullFileName);