diff --git a/widget/src/gtk2/nsScreenManagerGtk.cpp b/widget/src/gtk2/nsScreenManagerGtk.cpp
index 9780ae033a3..ef56857eac9 100644
--- a/widget/src/gtk2/nsScreenManagerGtk.cpp
+++ b/widget/src/gtk2/nsScreenManagerGtk.cpp
@@ -197,12 +197,12 @@ nsScreenManagerGtk :: Init()
     if (_XnrmIsActive && _XnrmQueryScreens &&
         _XnrmIsActive(GDK_DISPLAY())) {
       screenInfo = _XnrmQueryScreens(GDK_DISPLAY(), &numScreens);
+
+      // remember for the destructor, if we are really working with Xinerama
+      mXineramaIsActive = numScreens > 0;
     }
   }
 
-  // remember for the destructor, if we are really working with Xinerama
-  mXineramaIsActive = numScreens > 0;
-
   // screenInfo == NULL if either Xinerama couldn't be loaded or
   // isn't running on the current display
   if (!screenInfo || numScreens == 1) {