diff --git a/Fltk/Draw.cpp b/Fltk/Draw.cpp
index cfa0c1ac0df544835e985aed34f8da8633ce231c..d6ee794d85a8931d8862a5b7452a8d1794a42731 100644
--- a/Fltk/Draw.cpp
+++ b/Fltk/Draw.cpp
@@ -32,6 +32,8 @@ void DrawCurrentOpenglWindow(bool make_current)
   openglWindow *gl = GUI::instance()->getCurrentOpenglWindow();
   if(make_current) gl->make_current();
   gl->redraw();
+  glFlush();
+  GUI::instance()->check();
 }
 
 void DrawPlugin(void (*draw)(void *context))