diff --git a/src/Main/WindowBuilder.cxx b/src/Main/WindowBuilder.cxx
index 64b38021d..79fff968f 100644
--- a/src/Main/WindowBuilder.cxx
+++ b/src/Main/WindowBuilder.cxx
@@ -196,7 +196,6 @@ GraphicsWindow* WindowBuilder::buildWindow(const SGPropertyNode* winNode)
     if (traitsSet) {
         GraphicsContext* gc = GraphicsContext::createGraphicsContext(traits);
         if (gc) {
-            gc->realize();
             GraphicsWindow* window = WindowSystemAdapter::getWSA()
                 ->registerWindow(gc, traits->windowName);
             if (drawGUI)
@@ -223,7 +222,6 @@ GraphicsWindow* WindowBuilder::getDefaultWindow()
     traits->windowName = "FlightGear";
     GraphicsContext* gc = GraphicsContext::createGraphicsContext(traits);
     if (gc) {
-        gc->realize();
         defaultWindow = WindowSystemAdapter::getWSA()
             ->registerWindow(gc, defaultWindowName);
         return defaultWindow;
diff --git a/src/Main/fg_os_osgviewer.cxx b/src/Main/fg_os_osgviewer.cxx
index 8badbd6d1..058e31469 100644
--- a/src/Main/fg_os_osgviewer.cxx
+++ b/src/Main/fg_os_osgviewer.cxx
@@ -170,6 +170,8 @@ void fgOSMainLoop()
     ref_ptr<FGEventHandler> manipulator
         = globals->get_renderer()->getEventHandler();
     viewer->setReleaseContextAtEndOfFrameHint(false);
+    if (!viewer->isRealized())
+        viewer->realize();
     while (!viewer->done()) {
         fgIdleHandler idleFunc = manipulator->getIdleHandler();
         fgDrawHandler drawFunc = manipulator->getDrawHandler();