diff --git a/trailfocus.c b/trailfocus.c
index ff780ea..3b5068e 100644
--- a/trailfocus.c
+++ b/trailfocus.c
@@ -106,7 +106,12 @@ setWindows (CompScreen *s)
 	wasTfWindow = tw->isTfWindow;
 	tw->isTfWindow = TRUE;
 
-	if (w->invisible || w->hidden || w->minimized)
+	if (w->attrib.x < 0 || (w->attrib.x + w->attrib.width) > s->width ||
+	    w->attrib.y < 0 || (w->attrib.y + w->attrib.height) > s->height)
+	{
+	    tw->isTfWindow = FALSE;
+	}
+	else if (w->invisible || w->hidden || w->minimized || w->shaded)
 	    tw->isTfWindow = FALSE;
 	else if (!matchEval (trailfocusGetWindowMatch (s), w))
 	    tw->isTfWindow = FALSE;
@@ -294,6 +299,18 @@ trailfocusHandleEvent (CompDisplay *d,
 	if (s)
 	    setWindows (s);
 	break;
+    case PropertyNotify:
+	if (event->xproperty.atom == d->desktopViewportAtom)
+	{
+	    s = findScreenAtDisplay (d, event->xproperty.window);
+	    if (s)
+	    {
+	    	cleanList (s);
+		pushWindow (d, d->activeWindow);
+		setWindows (s);
+	    }
+	}
+	break;
     default:
 	break;
     }