diff --git a/README.md b/README.md
index 0649f85..bb6609c 100644
--- a/README.md
+++ b/README.md
@@ -138,6 +138,7 @@ In order to avoid lots of small changesets, a changeset is opened and kept open.
 
 Whenever a change is made -even adding a single tag- the change is uploaded into this changeset. If that fails, the changeset is probably closed and we open a new changeset.
 
+Note that changesets are closed automatically after one hour of inactivity, so we don't have to worry about closing them. 
 
 # Privacy
 
diff --git a/UI/SimpleAddUI.ts b/UI/SimpleAddUI.ts
index bb54bbf..3c5d58b 100644
--- a/UI/SimpleAddUI.ts
+++ b/UI/SimpleAddUI.ts
@@ -14,7 +14,7 @@ import {Utils} from "../Utils";
  * Asks to add a feature at the last clicked location, at least if zoom is sufficient
  */
 export class SimpleAddUI extends UIElement {
-    private _addButtons: UIElement[];
+    private readonly _addButtons: UIElement[];
     
     private _loginButton : UIElement;