diff --git a/src/core/client.mjs b/src/core/client.mjs
index 9899313..707151b 100644
--- a/src/core/client.mjs
+++ b/src/core/client.mjs
@@ -123,13 +123,18 @@ const insertPanel = async (api, db) => {
   const notionFrame = ".notion-frame",
     notionTopbarBtn = ".notion-topbar-more-button",
     togglePanelHotkey = await db.get("togglePanelHotkey"),
-    { html } = api;
+    { html, setState, addPanelView } = api;
 
   const $panel = html`<${Panel}
-      _getWidth=${() => db.get("sidePanelWidth")}
-      _setWidth=${(width) => db.set("sidePanelWidth", width)}
-      _getOpen=${() => db.get("sidePanelOpen")}
-      _setOpen=${(open) => db.set("sidePanelOpen", open)}
+      ...${Object.assign(
+        ...["Width", "Open", "View"].map((key) => ({
+          [`_get${key}`]: () => db.get(`sidePanel${key}`),
+          [`_set${key}`]: async (value) => {
+            await db.set(`sidePanel${key}`, value);
+            setState({ rerender: true });
+          },
+        }))
+      )}
     />`,
     togglePanel = () => {
       if ($panel.hasAttribute("open")) $panel.close();
diff --git a/src/core/islands/Panel.mjs b/src/core/islands/Panel.mjs
index fc00eb3..8142976 100644
--- a/src/core/islands/Panel.mjs
+++ b/src/core/islands/Panel.mjs
@@ -7,9 +7,73 @@
 import { Tooltip } from "./Tooltip.mjs";
 import { Select } from "../menu/islands/Select.mjs";
 
-function View(props) {
-  const { html } = globalThis.__enhancerApi;
-  return html``;
+// note: these islands do not accept extensible
+// properties, i.e. they are not reusable.
+// please register your own interfaces via
+// globalThis.__enhancerApi.addPanelView and
+// not by re-instantiating additional panels
+
+let panelViews = [],
+  // "$icon" may either be an actual dom element,
+  // or an icon name from the lucide icons set
+  addPanelView = ({ title, $icon, $view }) => {
+    panelViews.push([{ title, $icon }, $view]);
+    panelViews.sort(([{ title: a }], [{ title: b }]) => a.localeCompare(b));
+    const { setState } = globalThis.__enhancerApi;
+    setState?.({ panelViews });
+  },
+  removePanelView = ($view) => {
+    panelViews = panelViews.filter(([, v]) => v !== $view);
+    const { setState } = globalThis.__enhancerApi;
+    setState?.({ panelViews });
+  };
+
+function View({ _get }) {
+  const { html, setState, useState } = globalThis.__enhancerApi,
+    $container = html`<div
+      class="overflow-(y-auto x-hidden)
+      h-full min-w-[var(--panel--width)]"
+    ></div>`;
+  useState(["rerender"], async () => {
+    const openView = await _get?.(),
+      $view =
+        panelViews.find(([{ title }]) => {
+          return title === openView;
+        })?.[1] || panelViews[0]?.[1];
+    if (!$container.contains($view)) {
+      $container.innerHTML = "";
+      $container.append($view);
+    }
+  });
+  return $container;
+}
+
+function Switcher({ _get, _set, minWidth, maxWidth }) {
+  const { html, extendProps, setState, useState } = globalThis.__enhancerApi,
+    $switcher = html`<div
+      class="relative flex items-center
+      font-medium p-[8.5px] ml-[4px] grow"
+    ></div>`,
+    setView = (view) => {
+      _set?.(view);
+      setState({ activePanelView: view });
+    };
+  useState(["panelViews"], ([panelViews]) => {
+    const values = panelViews.map(([{ title, $icon }]) => {
+      // panel switcher internally uses the select island,
+      // which expects an option value rather than a title
+      return { value: title, $icon };
+    });
+    $switcher.innerHTML = "";
+    $switcher.append(html`<${Select}
+      popupMode="dropdown"
+      class="w-full text-left"
+      maxWidth=${maxWidth - 56}
+      minWidth=${minWidth - 56}
+      ...${{ _get, _set: setView, values }}
+    />`);
+  });
+  return $switcher;
 }
 
 function Panel({
@@ -17,91 +81,77 @@ function Panel({
   _setWidth,
   _getOpen,
   _setOpen,
+  _getView,
+  _setView,
   minWidth = 250,
   maxWidth = 640,
   transitionDuration = 300,
-  ...props
 }) {
-  const { html, extendProps, setState, useState } = globalThis.__enhancerApi,
-    { addMutationListener, removeMutationListener } = globalThis.__enhancerApi;
-  extendProps(props, {
-    class: `notion-enhancer--panel order-2 shrink-0
-    transition-[width] open:w-[var(--panel--width)]
-    border-l-1 border-[color:var(--theme--fg-border)]
-    relative bg-[color:var(--theme--bg-primary)] w-0
-    duration-[${transitionDuration}ms] group/panel`,
-  });
+  const { html, setState, useState } = globalThis.__enhancerApi,
+    { addMutationListener, removeMutationListener } = globalThis.__enhancerApi,
+    $panel = html`<aside
+      class="notion-enhancer--panel relative order-2
+      shrink-0 bg-[color:var(--theme--bg-primary)]
+      border-(l-1 [color:var(--theme--fg-border)])
+      transition-[width] w-[var(--panel--width,0)]
+      duration-[${transitionDuration}ms] group/panel"
+    >
+      <style>
+        .notion-frame {
+          flex-direction: row !important;
+        }
+        .notion-frame [role="progressbar"] {
+          padding-right: var(--panel--width);
+        }
+        .notion-frame [role="progressbar"] > div {
+          overflow-x: clip;
+        }
+      </style>
+      <div
+        class="flex justify-between items-center
+        border-(b [color:var(--theme--fg-border)])"
+      >
+        <${Switcher}
+          ...${{ _get: _getView, _set: _setView, minWidth, maxWidth }}
+        />
+        <button
+          aria-label="Close side panel"
+          class="user-select-none h-[24px] w-[24px] duration-[20ms]
+          transition inline-flex items-center justify-center mr-[10px]
+          rounded-[3px] hover:bg-[color:var(--theme--bg-hover)]"
+          onclick=${() => $panel.close()}
+        >
+          <i
+            class="i-chevrons-right w-[20px] h-[20px]
+            text-[color:var(--theme--fg-secondary)]"
+          />
+        </button>
+      </div>
+      <${View} ...${{ _get: _getView }} />
+    </aside>`;
 
-  const values = [
-      {
-        icon: "type",
-        value: "word counter",
-      },
-      {
-        // prettier-ignore
-        $icon: html`<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24">
-          <circle cx="5" cy="7" r="2.8"/>
-          <circle cx="5" cy="17" r="2.79"/>
-          <path d="M21,5.95H11c-0.55,0-1-0.45-1-1v0c0-0.55,0.45-1,1-1h10c0.55,0,1,0.45,1,1v0C22,5.5,21.55,5.95,21,5.95z"/>
-          <path d="M17,10.05h-6c-0.55,0-1-0.45-1-1v0c0-0.55,0.45-1,1-1h6c0.55,0,1,0.45,1,1v0C18,9.6,17.55,10.05,17,10.05z"/>
-          <path d="M21,15.95H11c-0.55,0-1-0.45-1-1v0c0-0.55,0.45-1,1-1h10c0.55,0,1,0.45,1,1v0C22,15.5,21.55,15.95,21,15.95z" />
-          <path d="M17,20.05h-6c-0.55,0-1-0.45-1-1v0c0-0.55,0.45-1,1-1h6c0.55,0,1,0.45,1,1v0C18,19.6,17.55,20.05,17,20.05z"/>
-        </svg>`,
-        value: "outliner",
-      },
-    ],
-    _get = () => useState(["panelView"])[0],
-    _set = (value) => {
-      setState({ panelView: value, rerender: true });
-    };
-
-  const $resize = html`<div
+  let preDragWidth,
+    dragStartX = 0;
+  const $resizeHandle = html`<div
       class="absolute h-full w-[3px] left-[-3px]
       z-10 transition duration-300 hover:(cursor-col-resize
       shadow-[var(--theme--fg-border)_-2px_0px_0px_0px_inset])
       active:cursor-text group-not-[open]/panel:hidden"
     ></div>`,
-    $close = html`<button
-      aria-label="Close side panel"
-      class="user-select-none h-[24px] w-[24px] duration-[20ms]
-      transition inline-flex items-center justify-center mr-[10px]
-      rounded-[3px] hover:bg-[color:var(--theme--bg-hover)]"
-    >
-      <i
-        class="i-chevrons-right w-[20px] h-[20px]
-        text-[color:var(--theme--fg-secondary)]"
-      />
-    </div>`,
-    $switcher = html`<div
-      class="relative flex items-center
-      font-medium p-[8.5px] ml-[4px] grow"
-    >
-      <${Select}
-        popupMode="dropdown"
-        class="w-full text-left"
-        maxWidth=${maxWidth - 56}
-        minWidth=${minWidth - 56}
-        ...${{ _get, _set, values }}
-      />
-    </div>`,
-    $view = html`<div
-      class="overflow-(y-auto x-hidden)
-      h-full min-w-[var(--panel--width)]"
-    ></div>`,
-    $panel = html`<aside ...${props}>
-      ${$resize}
-      <div
-        class="flex justify-between items-center
-        border-(b [color:var(--theme--fg-border)])"
-      >
-        ${$switcher}${$close}
-      </div>
-      ${$view}
-    </aside>`;
-
-  let preDragWidth,
-    dragStartX = 0;
-  const startDrag = async (event) => {
+    $resizeTooltip = html`<${Tooltip}>
+      <span>Drag</span> to resize<br />
+      <span>Click</span> to closed
+    <//>`,
+    showTooltip = (event) => {
+      setTimeout(() => {
+        const panelOpen = $panel.hasAttribute("open"),
+          handleHovered = $resizeHandle.matches(":hover");
+        if (!panelOpen || !handleHovered) return;
+        const { x } = $resizeHandle.getBoundingClientRect();
+        $resizeTooltip.show(x, event.clientY);
+      }, 200);
+    },
+    startDrag = async (event) => {
       dragStartX = event.clientX;
       preDragWidth = await _getWidth?.();
       if (isNaN(preDragWidth)) preDragWidth = minWidth;
@@ -121,32 +171,18 @@ function Panel({
       // trigger panel close if not resized
       if (dragStartX - event.clientX === 0) $panel.close();
     };
-  $resize.addEventListener("mousedown", startDrag);
-
-  const $tooltip = html`<${Tooltip}>
-      <span>Drag</span> to resize<br />
-      <span>Click</span> to closed
-    <//>`,
-    showTooltip = (event) => {
-      setTimeout(() => {
-        const panelOpen = $panel.hasAttribute("open"),
-          handleHovered = $resize.matches(":hover");
-        if (!panelOpen || !handleHovered) return;
-        const { x } = $resize.getBoundingClientRect();
-        $tooltip.show(x, event.clientY);
-      }, 200);
-    };
-  $resize.addEventListener("mouseover", showTooltip);
-  $resize.addEventListener("mouseout", () => $tooltip.hide());
-  $close.addEventListener("click", () => $panel.close());
+  $resizeHandle.addEventListener("mouseout", $resizeTooltip.hide);
+  $resizeHandle.addEventListener("mousedown", startDrag);
+  $resizeHandle.addEventListener("mouseover", showTooltip);
+  $panel.prepend($resizeHandle);
 
   // normally would place outside of an island, but in
   // this case is necessary for syncing up animations
   const notionHelp = ".notion-help-button",
-    repositionHelp = async () => {
+    repositionHelp = async (width) => {
       const $notionHelp = document.querySelector(notionHelp);
       if (!$notionHelp) return;
-      let width = await _getWidth?.();
+      width ??= await _getWidth?.();
       if (isNaN(width)) width = minWidth;
       if (!$panel.hasAttribute("open")) width = 0;
       const position = $notionHelp.style.getPropertyValue("right"),
@@ -163,15 +199,17 @@ function Panel({
   addMutationListener(notionHelp, repositionHelp);
 
   $panel.resize = async (width) => {
-    $tooltip.hide();
+    $resizeTooltip.hide();
     if (width) {
       width = Math.max(width, minWidth);
       width = Math.min(width, maxWidth);
       _setWidth?.(width);
     } else width = await _getWidth?.();
     if (isNaN(width)) width = minWidth;
-    $panel.style.setProperty("--panel--width", `${width}px`);
-    repositionHelp();
+    if (!$panel.hasAttribute("open")) width = 0;
+    const $cssVarTarget = $panel.parentElement || $panel;
+    $cssVarTarget.style.setProperty("--panel--width", `${width}px`);
+    repositionHelp(width);
   };
   $panel.open = () => {
     $panel.setAttribute("open", true);
@@ -182,13 +220,13 @@ function Panel({
     $panel.resize();
   };
   $panel.close = () => {
-    $tooltip.hide();
+    $resizeTooltip.hide();
     $panel.onbeforeclose?.();
     $panel.removeAttribute("open");
     $panel.style.pointerEvents = "auto";
     $panel.querySelectorAll("[tabindex]").forEach(($el) => ($el.tabIndex = -1));
+    $panel.resize();
     setState({ panelOpen: false });
-    repositionHelp();
     _setOpen(false);
     setTimeout(() => {
       $panel.style.pointerEvents = "";
@@ -198,8 +236,13 @@ function Panel({
   _getOpen().then((open) => {
     if (open) $panel.open();
   });
-
   return $panel;
 }
 
+globalThis.__enhancerApi ??= {};
+Object.assign(globalThis.__enhancerApi, {
+  addPanelView,
+  removePanelView,
+});
+
 export { Panel };
diff --git a/src/core/menu/islands/Select.mjs b/src/core/menu/islands/Select.mjs
index d0eab92..b3454f2 100644
--- a/src/core/menu/islands/Select.mjs
+++ b/src/core/menu/islands/Select.mjs
@@ -60,23 +60,25 @@ function Select({
     ></div>`;
 
   const options = values.map((opt) => {
-      if (typeof opt === "string") opt = { value: opt };
+      if (["string", "number"].includes(typeof opt)) opt = { value: opt };
       if (!(opt?.$icon instanceof Element)) {
-        if (opt?.icon && typeof opt.icon === "string") {
-          opt.$icon = html`<i class="i-${opt.icon} h-[16px] w-[16px]" />`;
+        if (typeof opt?.$icon === "string") {
+          opt.$icon = html`<i class="i-${opt.$icon} h-[16px] w-[16px]" />`;
         } else delete opt.$icon;
       }
-      opt.$option = html`<${Option} ...${{ ...opt, _get, _set }} />`;
-      opt.$selection = html`<div class="inline-flex items-center gap-[6px]">
-        <!-- swap icon/value order for correct display when dir="rtl" -->
-        <span>${opt.value}</span>${opt.$icon?.cloneNode(true) ?? ""}
-      </div>`;
-      return opt;
+      return {
+        ...opt,
+        $option: html`<${Option} ...${{ ...opt, _get, _set }} />`,
+        $value: html`<div class="inline-flex items-center gap-[6px]">
+          <!-- swap icon/value order for correct display when dir="rtl" -->
+          <span>${opt.value}</span>${opt.$icon?.cloneNode(true) ?? ""}
+        </div>`,
+      };
     }),
     getSelected = async () => {
       const value = (await _get?.()) ?? $select.innerText,
         option = options.find((opt) => opt.value === value);
-      if (!option) _set(options[0].value);
+      if (!option) _set?.(options[0].value);
       return option || options[0];
     },
     onKeydown = (event) => {
@@ -102,9 +104,9 @@ function Select({
   let _initialValue;
   useState(["rerender"], async () => {
     if (!options.length) return;
-    const { value, $selection } = await getSelected();
+    const { value, $value } = await getSelected();
     $select.innerHTML = "";
-    $select.append($selection);
+    $select.append($value);
     if (_requireReload) {
       _initialValue ??= value;
       if (value !== _initialValue) setState({ databaseUpdated: true });
diff --git a/src/shared/events.js b/src/shared/events.js
index 4214f1e..4ee92d1 100644
--- a/src/shared/events.js
+++ b/src/shared/events.js
@@ -6,6 +6,51 @@
 
 "use strict";
 
+// convenient util: batch event handling
+// every ___ ms to avoid over-handling &
+// any conflicts / perf.issues that may
+// otherwise result. a wait time of ~200ms
+// is recommended (the avg. human visual
+// reaction time is ~180-200ms)
+const debounce = (callback, wait = 200) => {
+  let timeoutId;
+  return (...args) => {
+    clearTimeout(timeoutId);
+    timeoutId = setTimeout(() => callback(...args), wait);
+  };
+};
+
+// provides basic key/value reactivity:
+// this is shared between all active mods,
+// i.e. mods can read and update other mods'
+// reactive states. this enables interop
+// between a mod's component islands and
+// supports inter-mod communication if so
+// required. caution should be used in
+// naming keys to avoid conflicts
+const _state = {},
+  _subscribers = [],
+  setState = (state) => {
+    Object.assign(_state, state);
+    const updates = Object.keys(state);
+    _subscribers
+      .filter(([keys]) => updates.some((key) => keys.includes(key)))
+      .forEach(([keys, callback]) => callback(keys.map((key) => _state[key])));
+  },
+  // useState(["keyA", "keyB"]) => returns [valueA, valueB]
+  // useState(["keyA", "keyB"], callback) => registers callback
+  // to be triggered after each update to either keyA or keyB,
+  // with [valueA, valueB] passed to the callback's first arg
+  useState = (keys, callback) => {
+    const state = keys.map((key) => _state[key]);
+    if (callback) {
+      callback = debounce(callback);
+      _subscribers.push([keys, callback]);
+      callback(state);
+    }
+    return state;
+  };
+
 let documentObserver,
   mutationListeners = [];
 const mutationQueue = [],
@@ -99,20 +144,21 @@ const modifierAliases = [
     }
   };
 document.addEventListener("keyup", (event) => {
-  const keyupListeners = keyListeners.filter(
-    ([, , waitForKeyup]) => waitForKeyup
-  );
+  const keyupListeners = keyListeners //
+    .filter(([, , waitForKeyup]) => waitForKeyup);
   handleKeypress(event, keyupListeners);
 });
 document.addEventListener("keydown", (event) => {
-  const keydownListeners = keyListeners.filter(
-    ([, , waitForKeyup]) => !waitForKeyup
-  );
+  const keydownListeners = keyListeners //
+    .filter(([, , waitForKeyup]) => !waitForKeyup);
   handleKeypress(event, keydownListeners);
 });
 
 globalThis.__enhancerApi ??= {};
 Object.assign(globalThis.__enhancerApi, {
+  debounce,
+  setState,
+  useState,
   addMutationListener,
   removeMutationListener,
   addKeyListener,
diff --git a/src/shared/markup.js b/src/shared/markup.js
index 8e768db..f08b274 100644
--- a/src/shared/markup.js
+++ b/src/shared/markup.js
@@ -560,7 +560,9 @@ const h = (type, props, ...children) => {
         } else elem.setAttribute(prop, props[prop]);
       } else elem[prop] = props[prop];
     }
-    elem.append(...children);
+    if (type === "style") {
+      elem.append(children.join("").replace(/\s+/g, " "));
+    } else elem.append(...children);
     return elem;
   },
   // combines instance-provided element props
@@ -586,38 +588,8 @@ const h = (type, props, ...children) => {
   },
   html = htm.bind(h);
 
-// provides basic key/value reactivity:
-// this is shared between all active mods,
-// i.e. mods can read and update other mods'
-// reactive states. this enables interop
-// between a mod's component islands and
-// supports inter-mod communication if so
-// required. caution should be used in
-// naming keys to avoid conflicts
-const _state = {},
-  _subscribers = [],
-  setState = (state) => {
-    Object.assign(_state, state);
-    const updates = Object.keys(state);
-    _subscribers
-      .filter(([keys]) => updates.some((key) => keys.includes(key)))
-      .forEach(([keys, callback]) => callback(keys.map((key) => _state[key])));
-  },
-  // useState(["keyA", "keyB"]) => returns [valueA, valueB]
-  // useState(["keyA", "keyB"], callback) => registers callback
-  // to be triggered after each update to either keyA or keyB,
-  // with [valueA, valueB] passed to the callback's first arg
-  useState = (keys, callback) => {
-    const state = keys.map((key) => _state[key]);
-    if (callback) _subscribers.push([keys, callback]);
-    callback?.(state);
-    return state;
-  };
-
 globalThis.__enhancerApi ??= {};
 Object.assign(globalThis.__enhancerApi, {
   html,
   extendProps,
-  setState,
-  useState,
 });
diff --git a/src/shared/registry.js b/src/shared/registry.js
index 84c1166..950ae94 100644
--- a/src/shared/registry.js
+++ b/src/shared/registry.js
@@ -65,7 +65,12 @@ const modDatabase = async (id) => {
   const optionDefaults =
     (await getMods())
       .find((mod) => mod.id === id)
-      ?.options?.map?.((opt) => [opt.key, opt.value ?? opt.values?.[0]])
+      ?.options?.map?.((opt) => {
+        let value = opt.value;
+        value ??= opt.values?.[0]?.value;
+        value ??= opt.values?.[0];
+        return [opt.key, value];
+      })
       ?.filter?.(([, value]) => typeof value !== "undefined") ?? {};
   return globalThis.__enhancerApi.initDatabase(
     [await getProfile(), id],