diff --git a/compositingprefs.cpp b/compositingprefs.cpp
index 3584e10cae..8c87ad4792 100644
--- a/compositingprefs.cpp
+++ b/compositingprefs.cpp
@@ -108,8 +108,7 @@ bool CompositingPrefs::createGLXContext()
     attribs << GLX_BLUE_SIZE << 1;
     attribs << None;
 
-    int scrnum = 0;  // correct?
-    XVisualInfo* visinfo = glXChooseVisual( display(), scrnum, attribs.data() );
+    XVisualInfo* visinfo = glXChooseVisual( display(), DefaultScreen( display()), attribs.data() );
     if( !visinfo )
         {
         attribs.last() = GLX_DOUBLEBUFFER;