Fixes a bug in JoglNewtDisplay: the canvas must be visible before retrieving or modifying the screen mode

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10015 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/jogl/com/jme3/system/jogl/JoglNewtDisplay.java

@@ -105,7 +105,10 @@ public class JoglNewtDisplay extends JoglNewtAbstractDisplay {
         canvas.setSize(settings.getWidth(), settings.getHeight());
         canvas.setUndecorated(settings.isFullscreen());
         canvas.setFullscreen(settings.isFullscreen());
-        //FIXME Does JMonkeyEngine 3.0 allow to change the resolution?
+        
+        // the canvas must be visible to allow the modification of the screen
+        //FIXME it should not be necessary
+        canvas.setVisible(true);
         /**
          * uses the filtering relying on resolution with the size to fetch only
          * the screen mode matching with the current resolution