diff --git a/cmd/syncthing/gui.go b/cmd/syncthing/gui.go
index 30fe2281..2cf441c2 100644
--- a/cmd/syncthing/gui.go
+++ b/cmd/syncthing/gui.go
@@ -1267,7 +1267,10 @@ func (s embeddedStatic) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 	w.Header().Set("Content-Length", fmt.Sprintf("%d", len(bs)))
 	w.Header().Set("Last-Modified", modified.UTC().Format(http.TimeFormat))
-	w.Header().Set("Cache-Control", "public")
+	// Strictly, no-cache means the same as this. However FF and IE treat no-cache as
+	// "don't hold a local cache at all", whereas everyone seems to treat this as
+	// you can hold a local cache, but you must revalidate it before using it.
+	w.Header().Set("Cache-Control", "max-age=0, must-revalidate")
 
 	w.Write(bs)
 }