Can delete a movement

moneymgr_web/src/widgets/NewMovementWidget.tsx

@@ -13,7 +13,7 @@ import { AmountInput } from "./forms/AmountInput";
 
 export function NewMovementWidget(p: {
   account: Account;
-  onCreated: () => {};
+  onCreated: () => void;
 }): React.ReactElement {
   const snackbar = useSnackbar();
   const alert = useAlert();
@@ -91,7 +91,7 @@ export function NewMovementWidget(p: {
         type="text"
         placeholder="Amount"
         style={{ flex: 1, maxWidth: "110px" }}
-        value={amount}
+        value={amount ?? 0}
         onValueChange={setAmount}
       />
       <Tooltip title="Add new movement">