diff --git a/containerbox.go b/containerbox.go
index b4f70b3..44d1d99 100644
--- a/containerbox.go
+++ b/containerbox.go
@@ -329,6 +329,8 @@ func (this *containerBox) recursiveRedo () {
 }
 
 func (this *containerBox) boxUnder (point image.Point, category eventCategory) anyBox {
+	if !point.In(this.bounds) { return nil }
+
 	if !this.capture[category] {
 		for _, box := range this.children {
 			candidate := box.(anyBox).boxUnder(point, category)
@@ -336,7 +338,7 @@ func (this *containerBox) boxUnder (point image.Point, category eventCategory) a
 		}
 	}
 
-	return this.box.boxUnder(point, category)
+	return this
 }
 
 func (this *containerBox) propagate (callback func (anyBox) bool) bool {