diff --git a/ui/src/message/Message.tsx b/ui/src/message/Message.tsx
index e4c8f2b..ffcefae 100644
--- a/ui/src/message/Message.tsx
+++ b/ui/src/message/Message.tsx
@@ -60,7 +60,7 @@ interface IProps {
 }
 
 class Message extends React.PureComponent<IProps & WithStyles<typeof styles>> {
-    private node: HTMLDivElement | null;
+    private node: HTMLDivElement | null = null;
 
     public componentDidMount = () =>
         this.props.height(this.node ? this.node.getBoundingClientRect().height : 0);
diff --git a/ui/src/snack/SnackManager.ts b/ui/src/snack/SnackManager.ts
index 60f7af9..d405bf3 100644
--- a/ui/src/snack/SnackManager.ts
+++ b/ui/src/snack/SnackManager.ts
@@ -8,7 +8,7 @@ export class SnackManager {
     @observable
     private messages: string[] = [];
     @observable
-    public message: string | null;
+    public message: string | null = null;
     @observable
     public counter = 0;