Saving my work and trying something a little different. Using a number as the id instead of the email address. I feel like this will also cause issues.

src/routes/sponsorships/10_view_modal__sponsorship_obj.svelte

@@ -3,6 +3,17 @@ import type { SvelteComponent } from 'svelte';
 import { onMount } from 'svelte';
 
 
+// This works and uses local storage:
+// store_current_tab must be prefixed with $ to be reactive.
+import { clipboard, FileDropzone, getModalStore, localStorageStore, ProgressRadial, RadioGroup, RadioItem, TabGroup, Tab, TabAnchor } from '@skeletonlabs/skeleton';
+
+import type { Writable } from 'svelte/store';
+
+import Element_data_store from '$lib/element_data_store.svelte';
+
+const store_current_tab: Writable<string> = localStorageStore('ae_sponsorships_current_tab', 'start');
+console.log(`store_current_tab:`, $store_current_tab);
+
 // This works and uses local storage:
 // store_current_tab must be prefixed with $ to be reactive.
 import { clipboard, FileDropzone, getModalStore, localStorageStore, ProgressRadial, RadioGroup, RadioItem, TabGroup, Tab, TabAnchor } from '@skeletonlabs/skeleton';