persist tab pane state, handle vertical scrolling in tab pane

ChatTwo/Http/Frontend/src/components/TabPane.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-    import { selectedTab, knownTabs, tabBarState } from "$lib/shared.svelte";
+    import { selectedTab, knownTabs, tabPaneState, closeTabPane } from "$lib/shared.svelte";
 
     async function selectTab(index: number) {
         const rawResponse = await fetch('/tab', {
@@ -13,17 +13,13 @@
         // const content = await rawResponse.json();
         // TODO: use the response
     }
-
-    function closeTabBar() {
-        tabBarState.visible = false;
-    }
 </script>
 
-<aside id="tabs" class:visible={tabBarState.visible}>
+<aside id="tabs" class:visible={tabPaneState.visible}>
     <div class="inner">
         <header>
             <span>Tabs</span>
-            <button type="button" onclick={() => closeTabBar()}>
+            <button type="button" onclick={() => closeTabPane()}>
                 <!-- "x" icon from https://github.com/feathericons/feather, under MIT license -->
                 <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/></svg>
             </button>

ChatTwo/Http/Frontend/src/components/TabPaneOpener.svelte

@@ -1,12 +1,13 @@
 <script lang="ts">
-    import { tabBarState } from "$lib/shared.svelte";
+    import { tabPaneState, openTabPane } from "$lib/shared.svelte";
 
     function onclick() {
-        tabBarState.visible = true;
+        openTabPane();
     }
 </script>
 
-<button type="button" aria-label="Open tab pane" class:visible={!tabBarState.visible} {onclick}>
+<button type="button" aria-label="Open tab pane" class:visible={!tabPaneState.visible} {onclick} disabled={tabPaneState.visible}>
+    <!-- "chevron-right" icon from https://github.com/feathericons/feather, under MIT license -->
     <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="9 18 15 12 9 6"/></svg>
 </button>
 

ChatTwo/Http/Frontend/src/lib/shared.svelte.ts

@@ -11,4 +11,15 @@ export interface ChannelOption {
 
 export const selectedTab: { index: number } = $state({ index: 0 });
 export const knownTabs: ChatTab[] = $state([]);
-export const tabBarState: { visible: boolean } = $state({ visible: false });
+export const tabPaneState: { visible: boolean } = $state({ visible: false });
+export const persistentTabPabeStateKey = 'chat2_tab_pane_visible';
+
+export function openTabPane() {
+    tabPaneState.visible = true;
+    window.localStorage.setItem(persistentTabPabeStateKey, 'true');
+}
+
+export function closeTabPane() {
+    tabPaneState.visible = false;
+    window.localStorage.setItem(persistentTabPabeStateKey, 'false');
+}

ChatTwo/Http/Frontend/src/routes/chat/+page.svelte

@@ -3,6 +3,7 @@
     import { Alert } from "@sveltestrap/sveltestrap";
     import { onMount } from 'svelte';
     import { ChatTwoWeb } from '$lib/chat.svelte'
+    import { tabPaneState, persistentTabPabeStateKey } from "$lib/shared.svelte";
     import { addGfdStylesheet } from "$lib/gfd";
     import DynamicTextArea from "../../components/DynamicTextArea.svelte";
     import ChannelSelector from "../../components/ChannelSelector.svelte";
@@ -30,6 +31,17 @@
         // Populate the stylesheet with gfd data
         addGfdStylesheet('/files/gfdata.gfd', '/files/fonticon_ps5.tex');
 
+        // read saved tab pane state from localStorage
+        try {
+            const tabPaneVisible = window.localStorage.getItem(persistentTabPabeStateKey);
+            if (tabPaneVisible !== null) {
+                tabPaneState.visible = JSON.parse(tabPaneVisible);
+            }
+        } catch (e) {
+            // JSON.parse() failed, let's reset what's in localStorage
+            window.localStorage.removeItem(persistentTabPabeStateKey);
+        }
+
         // Load all web functions in the background
         const _ = new ChatTwoWeb();
     });