Bugfix: draw descriptions only if button is active.

diff --git a/qwerty.py b/qwerty.py
index ba38160..7eb909a 100755
--- a/qwerty.py
+++ b/qwerty.py
@@ -156,7 +156,7 @@ class SuperButton(gtk.DrawingArea):
         cr.show_text(self.key)

         self.draw_label(cr)
-        if self.desc:
+        if self.desc and self.active:
             self.draw_desc(cr)

         if self.icon:
@@ -193,6 +193,7 @@ class SuperButton(gtk.DrawingArea):
         self.icon = None
         self.active = False
         self.running = False
+        self.desc = None
         self.cls = None
         self.queue_draw()