diff --git a/wasp/widgets.py b/wasp/widgets.py
index 556c7f5..9d80502 100644
--- a/wasp/widgets.py
+++ b/wasp/widgets.py
@@ -430,7 +430,9 @@ class Slider():
             v = 0
         elif v >= self._steps:
             v = self._steps - 1
+        changed = self.value != v
         self.value = v
+        return changed
 
 class Spinner():
     """A simple Spinner widget.