diff --git a/ui/models/fwdinghist.go b/ui/models/fwdinghist.go
index 78b42ee..b362d48 100644
--- a/ui/models/fwdinghist.go
+++ b/ui/models/fwdinghist.go
@@ -1,6 +1,7 @@
 package models
 
 import (
+	"github.com/google/martian/log"
 	"sort"
 	"sync"
 
@@ -67,6 +68,7 @@ func (t *FwdingHist) Update(events []*models.ForwardingEvent) {
 	defer t.mu.Unlock()
 	t.Clear()
 	for _, event := range events {
+		log.Debugf("update forwarding event: %v", event)
 		t.list = append(t.list, event)
 	}
 }