diff --git a/src/gtk/glcanvas.cpp b/src/gtk/glcanvas.cpp
index 301240283e..30def50299 100644
--- a/src/gtk/glcanvas.cpp
+++ b/src/gtk/glcanvas.cpp
@@ -355,6 +355,15 @@ bool wxGLCanvas::Create( wxWindow *parent,
     gtk_widget_pop_visual();
     gtk_widget_pop_colormap();
 
+    // if our parent window is already visible, we had been realized before we
+    // connected to the "realize" signal and hence our m_glContext hasn't been
+    // initialized yet and we have to do it now
+    if (GTK_WIDGET_REALIZED(m_wxwindow))
+        gtk_glwindow_realized_callback( m_wxwindow, this );
+
+    if (GTK_WIDGET_MAPPED(m_wxwindow))
+        gtk_glwindow_map_callback( m_wxwindow, this );
+
     return TRUE;
 }
 
diff --git a/src/gtk1/glcanvas.cpp b/src/gtk1/glcanvas.cpp
index 301240283e..30def50299 100644
--- a/src/gtk1/glcanvas.cpp
+++ b/src/gtk1/glcanvas.cpp
@@ -355,6 +355,15 @@ bool wxGLCanvas::Create( wxWindow *parent,
     gtk_widget_pop_visual();
     gtk_widget_pop_colormap();
 
+    // if our parent window is already visible, we had been realized before we
+    // connected to the "realize" signal and hence our m_glContext hasn't been
+    // initialized yet and we have to do it now
+    if (GTK_WIDGET_REALIZED(m_wxwindow))
+        gtk_glwindow_realized_callback( m_wxwindow, this );
+
+    if (GTK_WIDGET_MAPPED(m_wxwindow))
+        gtk_glwindow_map_callback( m_wxwindow, this );
+
     return TRUE;
 }