From b099746d712f4ff325ea579591fbe365b559e3a4 Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Sat, 22 Mar 2025 17:58:41 -0400
Subject: [PATCH 01/17] add stop at caught up preference

---
 src/features/scroll_to_bottom.js      | 9 +++++++++
 src/features/scroll_to_bottom.json    | 7 +++++++
 src/features/tweaks/caught_up_line.js | 4 ++--
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index e4ddb7dbd7..b6ac24b2c7 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -2,6 +2,8 @@ import { keyToClasses, keyToCss } from '../utils/css_map.js';
 import { translate } from '../utils/language_data.js';
 import { pageModifications } from '../utils/mutations.js';
 import { buildStyle } from '../utils/interface.js';
+import { getPreferences } from '../utils/preferences.js';
+import { borderAttribute, tagChicletCarouselLinkSelector } from './tweaks/caught_up_line.js';
 
 const scrollToBottomButtonId = 'xkit-scroll-to-bottom-button';
 $(`[id="${scrollToBottomButtonId}"]`).remove();
@@ -88,15 +90,22 @@ const addButtonToPage = async function ([scrollToTopButton]) {
   pageModifications.register('*', checkForButtonRemoved);
 };
 
+const onTagChicletCarouselItemsAdded = () => stopScrolling();
+
 export const main = async function () {
+  const { stopAtCaughtUp } = await getPreferences('scroll_to_bottom');
+
   pageModifications.register(`button[aria-label="${translate('Scroll to top')}"]`, addButtonToPage);
   pageModifications.register(knightRiderLoaderSelector, onLoadersAdded);
+  stopAtCaughtUp && pageModifications.register(`${tagChicletCarouselLinkSelector}, [${borderAttribute}]`, onTagChicletCarouselItemsAdded);
 };
 
 export const clean = async function () {
   pageModifications.unregister(addButtonToPage);
   pageModifications.unregister(checkForButtonRemoved);
   pageModifications.unregister(onLoadersAdded);
+  pageModifications.unregister(onTagChicletCarouselItemsAdded);
+
   stopScrolling();
   scrollToBottomButton?.remove();
 };
diff --git a/src/features/scroll_to_bottom.json b/src/features/scroll_to_bottom.json
index aaf7f404ab..59a35088cd 100644
--- a/src/features/scroll_to_bottom.json
+++ b/src/features/scroll_to_bottom.json
@@ -6,5 +6,12 @@
     "class_name": "ri-download-fill",
     "color": "#e8d738",
     "background_color": "black"
+  },
+  "preferences": {
+    "stopAtCaughtUp": {
+      "type": "checkbox",
+      "label": "Stop scrolling the Following feed when I reach the Changes/Trending/etc. carousel",
+      "default": true
+    }
   }
 }
diff --git a/src/features/tweaks/caught_up_line.js b/src/features/tweaks/caught_up_line.js
index 76ed0cd3ed..640e863f44 100644
--- a/src/features/tweaks/caught_up_line.js
+++ b/src/features/tweaks/caught_up_line.js
@@ -4,7 +4,7 @@ import { pageModifications } from '../../utils/mutations.js';
 import { followingTimelineSelector } from '../../utils/timeline_id.js';
 
 const hiddenAttribute = 'data-tweaks-caught-up-line-title';
-const borderAttribute = 'data-tweaks-caught-up-line-border';
+export const borderAttribute = 'data-tweaks-caught-up-line-border';
 
 export const styleElement = buildStyle(`
   [${hiddenAttribute}] > div { display: none; }
@@ -24,7 +24,7 @@ export const styleElement = buildStyle(`
 `);
 
 const listTimelineObjectSelector = keyToCss('listTimelineObject');
-const tagChicletCarouselLinkSelector = `${followingTimelineSelector} ${listTimelineObjectSelector} ${keyToCss('tagChicletLink')}`;
+export const tagChicletCarouselLinkSelector = `${followingTimelineSelector} ${listTimelineObjectSelector} ${keyToCss('tagChicletLink')}`;
 
 const createCaughtUpLine = tagChicletCarouselItems => tagChicletCarouselItems
   .map(getTimelineItemWrapper)

From a9066e3bccc5e3601dd5e7f84068befd76e401d1 Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Tue, 15 Apr 2025 21:34:36 -0700
Subject: [PATCH 02/17] scroll to carousel itself

---
 src/features/scroll_to_bottom.js | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index b6ac24b2c7..6575b2e062 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -1,7 +1,7 @@
 import { keyToClasses, keyToCss } from '../utils/css_map.js';
 import { translate } from '../utils/language_data.js';
 import { pageModifications } from '../utils/mutations.js';
-import { buildStyle } from '../utils/interface.js';
+import { buildStyle, getTimelineItemWrapper } from '../utils/interface.js';
 import { getPreferences } from '../utils/preferences.js';
 import { borderAttribute, tagChicletCarouselLinkSelector } from './tweaks/caught_up_line.js';
 
@@ -90,7 +90,15 @@ const addButtonToPage = async function ([scrollToTopButton]) {
   pageModifications.register('*', checkForButtonRemoved);
 };
 
-const onTagChicletCarouselItemsAdded = () => stopScrolling();
+const onTagChicletCarouselItemsAdded = ([carousel]) => {
+  if (active) {
+    stopScrolling();
+
+    const titleElement = getTimelineItemWrapper(carousel)?.previousElementSibling;
+    const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
+    titleElementTop && window.scrollBy({ top: titleElementTop });
+  }
+};
 
 export const main = async function () {
   const { stopAtCaughtUp } = await getPreferences('scroll_to_bottom');

From 46bf6e5acd92d0bfd798be60b00b0b70743fe669 Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Tue, 15 Apr 2025 21:34:41 -0700
Subject: [PATCH 03/17] test code

---
 src/features/scroll_to_bottom.js | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index 6575b2e062..a931956682 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -49,6 +49,11 @@ const startScrolling = () => {
   active = true;
   scrollToBottomButton.classList.add(activeClass);
   scrollToBottom();
+
+  const temp = document.querySelector(`${tagChicletCarouselLinkSelector}, [${borderAttribute}]`);
+  if (temp) {
+    onTagChicletCarouselItemsAdded([temp]);
+  }
 };
 
 const stopScrolling = () => {

From 2929c791cd67e0b9bc51dd39ab8dc073f88d3ea9 Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Tue, 15 Apr 2025 21:34:45 -0700
Subject: [PATCH 04/17] Revert "test code"

This reverts commit 9fe679ec7648cd1f00db86abfe1c16d7236fc1a9.
---
 src/features/scroll_to_bottom.js | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index a931956682..6575b2e062 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -49,11 +49,6 @@ const startScrolling = () => {
   active = true;
   scrollToBottomButton.classList.add(activeClass);
   scrollToBottom();
-
-  const temp = document.querySelector(`${tagChicletCarouselLinkSelector}, [${borderAttribute}]`);
-  if (temp) {
-    onTagChicletCarouselItemsAdded([temp]);
-  }
 };
 
 const stopScrolling = () => {

From b8bb1eab03fe0904c270368bf9ce3116875d89b6 Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Wed, 16 Apr 2025 12:09:22 -0700
Subject: [PATCH 05/17] no really this time we are waiting long enough.

does this look fun to you
---
 src/features/scroll_to_bottom.js | 10 ++++++----
 src/utils/interface.js           | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index 6575b2e062..d54da84684 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -1,7 +1,7 @@
 import { keyToClasses, keyToCss } from '../utils/css_map.js';
 import { translate } from '../utils/language_data.js';
 import { pageModifications } from '../utils/mutations.js';
-import { buildStyle, getTimelineItemWrapper } from '../utils/interface.js';
+import { buildStyle, getTimelineItemWrapper, waitForScroller } from '../utils/interface.js';
 import { getPreferences } from '../utils/preferences.js';
 import { borderAttribute, tagChicletCarouselLinkSelector } from './tweaks/caught_up_line.js';
 
@@ -94,9 +94,11 @@ const onTagChicletCarouselItemsAdded = ([carousel]) => {
   if (active) {
     stopScrolling();
 
-    const titleElement = getTimelineItemWrapper(carousel)?.previousElementSibling;
-    const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
-    titleElementTop && window.scrollBy({ top: titleElementTop });
+    waitForScroller().then(() => {
+      const titleElement = getTimelineItemWrapper(carousel)?.previousElementSibling;
+      const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
+      titleElementTop && window.scrollBy({ top: titleElementTop });
+    });
   }
 };
 
diff --git a/src/utils/interface.js b/src/utils/interface.js
index 1dfe202fdc..dbd0bb021d 100644
--- a/src/utils/interface.js
+++ b/src/utils/interface.js
@@ -144,3 +144,24 @@ export const appendWithoutOverflow = (element, target, defaultPosition = 'below'
     element.style.setProperty('--horizontal-offset', `${preventOverflowTargetRect.right - 15 - elementRect.right}px`);
   }
 };
+
+export const wait = async ({ ms, msTimes = 1, frames }) => {
+  if (ms !== undefined) {
+    for (let i = 0; i < msTimes; i++) {
+      await new Promise(resolve => setTimeout(resolve, ms));
+    }
+  }
+  for (let i = 0; i < frames; i++) {
+    await new Promise(requestAnimationFrame);
+  }
+};
+
+/**
+ * @returns {Promise<void>} - Attempts to resolve after Tumblr's endless scrolling code has stopped updating
+ */
+export const waitForScroller = () =>
+  wait({
+    ms: 100, // matches the debounce delay on tumblr's `scheduleUpdate` virtual scroller function
+    msTimes: 3, // arbitrary, high-enough-in-practice number
+    frames: 1
+  });

From e187d6fb63beb6bdaa4e0bc809e3adfc5069156e Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Wed, 16 Apr 2025 12:09:34 -0700
Subject: [PATCH 06/17] test code

---
 src/features/scroll_to_bottom.js | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index d54da84684..7f340bd02b 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -105,6 +105,16 @@ const onTagChicletCarouselItemsAdded = ([carousel]) => {
 export const main = async function () {
   const { stopAtCaughtUp } = await getPreferences('scroll_to_bottom');
 
+  pageModifications.register('[tabindex="-1"][data-id]', (postElements) => {
+    for (const postElement of postElements) {
+      if (Math.random() < 0.05) {
+        console.log('simulating scroll stop', getTimelineItemWrapper(postElement));
+        onTagChicletCarouselItemsAdded([getTimelineItemWrapper(postElement)]);
+        break;
+      }
+    }
+  });
+
   pageModifications.register(`button[aria-label="${translate('Scroll to top')}"]`, addButtonToPage);
   pageModifications.register(knightRiderLoaderSelector, onLoadersAdded);
   stopAtCaughtUp && pageModifications.register(`${tagChicletCarouselLinkSelector}, [${borderAttribute}]`, onTagChicletCarouselItemsAdded);

From ad58dd0cc8d87c63574ee6036cde3ac3b40cb47d Mon Sep 17 00:00:00 2001
From: Marcus <marcustyphoon@gmail.com>
Date: Wed, 16 Apr 2025 12:09:39 -0700
Subject: [PATCH 07/17] Revert "test code"

This reverts commit dc967739501af97c15aa279b69d31cbc79722578.
---
 src/features/scroll_to_bottom.js | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/src/features/scroll_to_bottom.js b/src/features/scroll_to_bottom.js
index 7f340bd02b..d54da84684 100644
--- a/src/features/scroll_to_bottom.js
+++ b/src/features/scroll_to_bottom.js
@@ -105,16 +105,6 @@ const onTagChicletCarouselItemsAdded = ([carousel]) => {
 export const main = async function () {
   const { stopAtCaughtUp } = await getPreferences('scroll_to_bottom');
 
-  pageModifications.register('[tabindex="-1"][data-id]', (postElements) => {
-    for (const postElement of postElements) {
-      if (Math.random() < 0.05) {
-        console.log('simulating scroll stop', getTimelineItemWrapper(postElement));
-        onTagChicletCarouselItemsAdded([getTimelineItemWrapper(postElement)]);
-        break;
-      }
-    }
-  });
-
   pageModifications.register(`button[aria-label="${translate('Scroll to top')}"]`, addButtonToPage);
   pageModifications.register(knightRiderLoaderSelector, onLoadersAdded);
   stopAtCaughtUp && pageModifications.register(`${tagChicletCarouselLinkSelector}, [${borderAttribute}]`, onTagChicletCarouselItemsAdded);

From a4c0062453b7f66842e45116f573e994a069eaf4 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Tue, 19 Aug 2025 21:23:24 -0400
Subject: [PATCH 08/17] new method: check every cell

---
 src/features/scroll_to_bottom/index.js | 32 ++++++++++++++++----------
 src/features/tweaks/caught_up_line.js  |  4 ++--
 src/main_world/unbury_cell_item.js     | 14 +++++++++++
 src/utils/react_props.js               |  8 +++++++
 4 files changed, 44 insertions(+), 14 deletions(-)
 create mode 100644 src/main_world/unbury_cell_item.js

diff --git a/src/features/scroll_to_bottom/index.js b/src/features/scroll_to_bottom/index.js
index 250f8d5f63..70b3cdc2c9 100644
--- a/src/features/scroll_to_bottom/index.js
+++ b/src/features/scroll_to_bottom/index.js
@@ -1,9 +1,9 @@
 import { keyToClasses, keyToCss } from '../../utils/css_map.js';
 import { translate } from '../../utils/language_data.js';
 import { pageModifications } from '../../utils/mutations.js';
-import { buildStyle, getTimelineItemWrapper, waitForScroller } from '../../utils/interface.js';
+import { buildStyle, waitForScroller } from '../../utils/interface.js';
 import { getPreferences } from '../../utils/preferences.js';
-import { borderAttribute, tagChicletCarouselLinkSelector } from './../tweaks/caught_up_line.js';
+import { cellItem } from '../../utils/react_props.js';
 
 const scrollToBottomButtonId = 'xkit-scroll-to-bottom-button';
 $(`[id="${scrollToBottomButtonId}"]`).remove();
@@ -90,15 +90,23 @@ const addButtonToPage = async function ([scrollToTopButton]) {
   pageModifications.register('*', checkForButtonRemoved);
 };
 
-const onTagChicletCarouselItemsAdded = ([carousel]) => {
-  if (active) {
-    stopScrolling();
+const caughtUpCarouselObjectType = 'followed_tag_carousel_card';
 
-    waitForScroller().then(() => {
-      const titleElement = getTimelineItemWrapper(carousel)?.previousElementSibling;
-      const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
-      titleElementTop && window.scrollBy({ top: titleElementTop });
-    });
+const onCellsAdded = async cells => {
+  if (active) {
+    for (const cell of cells) {
+      const item = await cellItem(cell);
+      if (item.elements?.some(({ objectType }) => objectType === caughtUpCarouselObjectType)) {
+        stopScrolling();
+
+        waitForScroller().then(() => {
+          const titleElement = cell?.previousElementSibling;
+          const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
+          titleElementTop && window.scrollBy({ top: titleElementTop });
+        });
+        return;
+      }
+    }
   }
 };
 
@@ -107,14 +115,14 @@ export const main = async function () {
 
   pageModifications.register(`button[aria-label="${translate('Scroll to top')}"]`, addButtonToPage);
   pageModifications.register(knightRiderLoaderSelector, onLoadersAdded);
-  stopAtCaughtUp && pageModifications.register(`${tagChicletCarouselLinkSelector}, [${borderAttribute}]`, onTagChicletCarouselItemsAdded);
+  stopAtCaughtUp && pageModifications.register(keyToCss(('cell')), onCellsAdded);
 };
 
 export const clean = async function () {
   pageModifications.unregister(addButtonToPage);
   pageModifications.unregister(checkForButtonRemoved);
   pageModifications.unregister(onLoadersAdded);
-  pageModifications.unregister(onTagChicletCarouselItemsAdded);
+  pageModifications.unregister(onCellsAdded);
 
   stopScrolling();
   scrollToBottomButton?.remove();
diff --git a/src/features/tweaks/caught_up_line.js b/src/features/tweaks/caught_up_line.js
index 640e863f44..76ed0cd3ed 100644
--- a/src/features/tweaks/caught_up_line.js
+++ b/src/features/tweaks/caught_up_line.js
@@ -4,7 +4,7 @@ import { pageModifications } from '../../utils/mutations.js';
 import { followingTimelineSelector } from '../../utils/timeline_id.js';
 
 const hiddenAttribute = 'data-tweaks-caught-up-line-title';
-export const borderAttribute = 'data-tweaks-caught-up-line-border';
+const borderAttribute = 'data-tweaks-caught-up-line-border';
 
 export const styleElement = buildStyle(`
   [${hiddenAttribute}] > div { display: none; }
@@ -24,7 +24,7 @@ export const styleElement = buildStyle(`
 `);
 
 const listTimelineObjectSelector = keyToCss('listTimelineObject');
-export const tagChicletCarouselLinkSelector = `${followingTimelineSelector} ${listTimelineObjectSelector} ${keyToCss('tagChicletLink')}`;
+const tagChicletCarouselLinkSelector = `${followingTimelineSelector} ${listTimelineObjectSelector} ${keyToCss('tagChicletLink')}`;
 
 const createCaughtUpLine = tagChicletCarouselItems => tagChicletCarouselItems
   .map(getTimelineItemWrapper)
diff --git a/src/main_world/unbury_cell_item.js b/src/main_world/unbury_cell_item.js
new file mode 100644
index 0000000000..66e5ea55c4
--- /dev/null
+++ b/src/main_world/unbury_cell_item.js
@@ -0,0 +1,14 @@
+export default function unburyCellItem () {
+  const postElement = this;
+  const reactKey = Object.keys(postElement).find(key => key.startsWith('__reactFiber'));
+  let fiber = postElement[reactKey];
+
+  while (fiber !== null) {
+    const { item } = fiber.memoizedProps || {};
+    if (item !== undefined) {
+      return item;
+    } else {
+      fiber = fiber.return;
+    }
+  }
+}
diff --git a/src/utils/react_props.js b/src/utils/react_props.js
index 6a0a952de0..d50f66e4ca 100644
--- a/src/utils/react_props.js
+++ b/src/utils/react_props.js
@@ -10,6 +10,14 @@ export const timelineObject = weakMemoize(postElement =>
   inject('/main_world/unbury_timeline_object.js', [], postElement)
 );
 
+/**
+ * @param {Element} cellElement - An on-screen timeline cell
+ * @returns {Promise<object>} - The post's buried item property
+ */
+export const cellItem = weakMemoize(cellElement =>
+  inject('/main_world/unbury_cell_item.js', [], cellElement)
+);
+
 /**
  * @param {Element} notificationElement - An on-screen notification
  * @returns {Promise<object>} - The notification's buried notification property

From bc1993a1406712e5a4dcf1c487fe1dc8d2cc4335 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Wed, 20 Aug 2025 10:31:38 -0400
Subject: [PATCH 09/17] fixes

---
 src/main_world/unbury_cell_item.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main_world/unbury_cell_item.js b/src/main_world/unbury_cell_item.js
index 66e5ea55c4..1652a465a3 100644
--- a/src/main_world/unbury_cell_item.js
+++ b/src/main_world/unbury_cell_item.js
@@ -1,7 +1,7 @@
 export default function unburyCellItem () {
-  const postElement = this;
-  const reactKey = Object.keys(postElement).find(key => key.startsWith('__reactFiber'));
-  let fiber = postElement[reactKey];
+  const cellElement = this;
+  const reactKey = Object.keys(cellElement).find(key => key.startsWith('__reactFiber'));
+  let fiber = cellElement[reactKey];
 
   while (fiber !== null) {
     const { item } = fiber.memoizedProps || {};

From ca2b3b2e804107ca46916ca1baad3c0c4c18f5b4 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Wed, 20 Aug 2025 10:31:54 -0400
Subject: [PATCH 10/17] initial click behavior

---
 src/features/scroll_to_bottom/index.js | 46 +++++++++++++++++---------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/src/features/scroll_to_bottom/index.js b/src/features/scroll_to_bottom/index.js
index 70b3cdc2c9..a5646510c2 100644
--- a/src/features/scroll_to_bottom/index.js
+++ b/src/features/scroll_to_bottom/index.js
@@ -15,6 +15,7 @@ ${keyToCss('notifications')} + div
 `;
 const knightRiderLoaderSelector = `:is(${loaderSelector}) > ${keyToCss('knightRiderLoader')}`;
 
+let stopAtCaughtUp;
 let scrollToBottomButton;
 let active = false;
 
@@ -44,7 +45,9 @@ const scrollToBottom = () => {
 };
 const observer = new ResizeObserver(scrollToBottom);
 
-const startScrolling = () => {
+const startScrolling = async () => {
+  if (stopAtCaughtUp && await scrollToCaughtUp()) return;
+
   observer.observe(document.documentElement);
   active = true;
   scrollToBottomButton.classList.add(activeClass);
@@ -92,26 +95,37 @@ const addButtonToPage = async function ([scrollToTopButton]) {
 
 const caughtUpCarouselObjectType = 'followed_tag_carousel_card';
 
-const onCellsAdded = async cells => {
-  if (active) {
-    for (const cell of cells) {
-      const item = await cellItem(cell);
-      if (item.elements?.some(({ objectType }) => objectType === caughtUpCarouselObjectType)) {
-        stopScrolling();
-
-        waitForScroller().then(() => {
-          const titleElement = cell?.previousElementSibling;
-          const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
-          titleElementTop && window.scrollBy({ top: titleElementTop });
-        });
-        return;
-      }
+const scrollToCaughtUp = async (addedCells) => {
+  const isStarting = !active;
+  for (const cell of isStarting ? [...document.querySelectorAll(keyToCss('cell'))] : addedCells) {
+    const item = await cellItem(cell);
+    if (item.elements?.some(({ objectType }) => objectType === caughtUpCarouselObjectType)) {
+      if (!isStarting) stopScrolling();
+      if (!isStarting) await waitForScroller();
+
+      const titleElement = cell?.previousElementSibling;
+      const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
+      if (!titleElementTop) continue;
+
+      const isAboveViewportBottom = titleElementTop < window.innerHeight;
+      if (isStarting && isAboveViewportBottom) continue;
+
+      window.scrollBy({ top: titleElementTop });
+      console.log(
+        isStarting
+          ? 'Scroll to Bottom scrolled down to existing carousel:'
+          : 'Scroll to Bottom scrolled to newly added carousel:',
+        titleElement
+      );
+      return true;
     }
   }
 };
 
+const onCellsAdded = addedCells => active && scrollToCaughtUp(addedCells);
+
 export const main = async function () {
-  const { stopAtCaughtUp } = await getPreferences('scroll_to_bottom');
+  ({ stopAtCaughtUp } = await getPreferences('scroll_to_bottom'));
 
   pageModifications.register(`button[aria-label="${translate('Scroll to top')}"]`, addButtonToPage);
   pageModifications.register(knightRiderLoaderSelector, onLoadersAdded);

From 32ac953886d0fc0be71c740b0c18a05a5210f346 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Wed, 20 Aug 2025 13:45:40 -0400
Subject: [PATCH 11/17] less arcane reliable scroll

---
 src/features/scroll_to_bottom/index.js | 50 ++++++++++++++++++--------
 src/utils/interface.js                 | 21 -----------
 2 files changed, 36 insertions(+), 35 deletions(-)

diff --git a/src/features/scroll_to_bottom/index.js b/src/features/scroll_to_bottom/index.js
index a5646510c2..0551c01d36 100644
--- a/src/features/scroll_to_bottom/index.js
+++ b/src/features/scroll_to_bottom/index.js
@@ -1,7 +1,7 @@
 import { keyToClasses, keyToCss } from '../../utils/css_map.js';
 import { translate } from '../../utils/language_data.js';
 import { pageModifications } from '../../utils/mutations.js';
-import { buildStyle, waitForScroller } from '../../utils/interface.js';
+import { buildStyle } from '../../utils/interface.js';
 import { getPreferences } from '../../utils/preferences.js';
 import { cellItem } from '../../utils/react_props.js';
 
@@ -93,28 +93,50 @@ const addButtonToPage = async function ([scrollToTopButton]) {
   pageModifications.register('*', checkForButtonRemoved);
 };
 
+const debounce = (func, ms) => {
+  let timeoutID;
+  return (...args) => {
+    clearTimeout(timeoutID);
+    timeoutID = setTimeout(() => func(...args), ms);
+  };
+};
+
+const reliablyScrollToTarget = target => {
+  const callback = () => {
+    window.scrollBy({ top: target?.getBoundingClientRect?.()?.top });
+    debouncedCancel();
+  };
+  const observer = new ResizeObserver(callback);
+  const debouncedCancel = debounce(() => {
+    console.log('disconnected reliablyScrollToTarget observer');
+    observer.disconnect();
+  }, 500);
+  observer.observe(document.documentElement);
+  callback();
+};
+
 const caughtUpCarouselObjectType = 'followed_tag_carousel_card';
 
 const scrollToCaughtUp = async (addedCells) => {
-  const isStarting = !active;
-  for (const cell of isStarting ? [...document.querySelectorAll(keyToCss('cell'))] : addedCells) {
+  for (const cell of addedCells || [...document.querySelectorAll(keyToCss('cell'))]) {
     const item = await cellItem(cell);
     if (item.elements?.some(({ objectType }) => objectType === caughtUpCarouselObjectType)) {
-      if (!isStarting) stopScrolling();
-      if (!isStarting) await waitForScroller();
-
       const titleElement = cell?.previousElementSibling;
-      const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
-      if (!titleElementTop) continue;
+      if (!titleElement) continue;
 
-      const isAboveViewportBottom = titleElementTop < window.innerHeight;
-      if (isStarting && isAboveViewportBottom) continue;
+      if (active) {
+        stopScrolling();
+      } else {
+        const titleElementTop = titleElement?.getBoundingClientRect?.()?.top;
+        const isAboveViewportBottom = titleElementTop !== undefined && titleElementTop < window.innerHeight;
+        if (isAboveViewportBottom) continue;
+      }
 
-      window.scrollBy({ top: titleElementTop });
+      reliablyScrollToTarget(titleElement);
       console.log(
-        isStarting
-          ? 'Scroll to Bottom scrolled down to existing carousel:'
-          : 'Scroll to Bottom scrolled to newly added carousel:',
+        addedCells
+          ? 'Scroll to Bottom scrolled to newly added carousel:'
+          : 'Scroll to Bottom scrolled down to existing carousel:',
         titleElement
       );
       return true;
diff --git a/src/utils/interface.js b/src/utils/interface.js
index 85b54a079d..c6e0dc50aa 100644
--- a/src/utils/interface.js
+++ b/src/utils/interface.js
@@ -146,24 +146,3 @@ export const appendWithoutOverflow = (element, target, defaultPosition = 'below'
     element.style.setProperty('--horizontal-offset', `${preventOverflowTargetRect.left + 15 - elementRect.left}px`);
   }
 };
-
-export const wait = async ({ ms, msTimes = 1, frames }) => {
-  if (ms !== undefined) {
-    for (let i = 0; i < msTimes; i++) {
-      await new Promise(resolve => setTimeout(resolve, ms));
-    }
-  }
-  for (let i = 0; i < frames; i++) {
-    await new Promise(requestAnimationFrame);
-  }
-};
-
-/**
- * @returns {Promise<void>} - Attempts to resolve after Tumblr's endless scrolling code has stopped updating
- */
-export const waitForScroller = () =>
-  wait({
-    ms: 100, // matches the debounce delay on tumblr's `scheduleUpdate` virtual scroller function
-    msTimes: 3, // arbitrary, high-enough-in-practice number
-    frames: 1
-  });

From 0703ed8ae219e3983c905b658557ed78ca271ce6 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Wed, 20 Aug 2025 14:47:28 -0400
Subject: [PATCH 12/17] extract debounce util

---
 src/features/scroll_to_bottom/index.js | 9 +--------
 src/utils/debounce.js                  | 7 +++++++
 2 files changed, 8 insertions(+), 8 deletions(-)
 create mode 100644 src/utils/debounce.js

diff --git a/src/features/scroll_to_bottom/index.js b/src/features/scroll_to_bottom/index.js
index 0551c01d36..3f122d5b98 100644
--- a/src/features/scroll_to_bottom/index.js
+++ b/src/features/scroll_to_bottom/index.js
@@ -4,6 +4,7 @@ import { pageModifications } from '../../utils/mutations.js';
 import { buildStyle } from '../../utils/interface.js';
 import { getPreferences } from '../../utils/preferences.js';
 import { cellItem } from '../../utils/react_props.js';
+import { debounce } from '../../utils/debounce.js';
 
 const scrollToBottomButtonId = 'xkit-scroll-to-bottom-button';
 $(`[id="${scrollToBottomButtonId}"]`).remove();
@@ -93,14 +94,6 @@ const addButtonToPage = async function ([scrollToTopButton]) {
   pageModifications.register('*', checkForButtonRemoved);
 };
 
-const debounce = (func, ms) => {
-  let timeoutID;
-  return (...args) => {
-    clearTimeout(timeoutID);
-    timeoutID = setTimeout(() => func(...args), ms);
-  };
-};
-
 const reliablyScrollToTarget = target => {
   const callback = () => {
     window.scrollBy({ top: target?.getBoundingClientRect?.()?.top });
diff --git a/src/utils/debounce.js b/src/utils/debounce.js
new file mode 100644
index 0000000000..7b268af262
--- /dev/null
+++ b/src/utils/debounce.js
@@ -0,0 +1,7 @@
+export const debounce = (func, ms) => {
+  let timeoutID;
+  return (...args) => {
+    clearTimeout(timeoutID);
+    timeoutID = setTimeout(() => func(...args), ms);
+  };
+};

From cda6c455a710a2501930ff25fcc133a065e6399b Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Wed, 20 Aug 2025 14:51:19 -0400
Subject: [PATCH 13/17] remove test logging

---
 src/features/scroll_to_bottom/index.js | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/src/features/scroll_to_bottom/index.js b/src/features/scroll_to_bottom/index.js
index 3f122d5b98..9203d1ad0e 100644
--- a/src/features/scroll_to_bottom/index.js
+++ b/src/features/scroll_to_bottom/index.js
@@ -100,10 +100,7 @@ const reliablyScrollToTarget = target => {
     debouncedCancel();
   };
   const observer = new ResizeObserver(callback);
-  const debouncedCancel = debounce(() => {
-    console.log('disconnected reliablyScrollToTarget observer');
-    observer.disconnect();
-  }, 500);
+  const debouncedCancel = debounce(() => observer.disconnect(), 500);
   observer.observe(document.documentElement);
   callback();
 };
@@ -126,12 +123,6 @@ const scrollToCaughtUp = async (addedCells) => {
       }
 
       reliablyScrollToTarget(titleElement);
-      console.log(
-        addedCells
-          ? 'Scroll to Bottom scrolled to newly added carousel:'
-          : 'Scroll to Bottom scrolled down to existing carousel:',
-        titleElement
-      );
       return true;
     }
   }

From edd4aaf05510da4a96301d53408fe9ebda880914 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Wed, 20 Aug 2025 15:01:16 -0400
Subject: [PATCH 14/17] variable name tweak

---
 src/features/scroll_to_bottom/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/features/scroll_to_bottom/index.js b/src/features/scroll_to_bottom/index.js
index 9203d1ad0e..2a28d471a9 100644
--- a/src/features/scroll_to_bottom/index.js
+++ b/src/features/scroll_to_bottom/index.js
@@ -97,10 +97,10 @@ const addButtonToPage = async function ([scrollToTopButton]) {
 const reliablyScrollToTarget = target => {
   const callback = () => {
     window.scrollBy({ top: target?.getBoundingClientRect?.()?.top });
-    debouncedCancel();
+    debouncedDisconnect();
   };
   const observer = new ResizeObserver(callback);
-  const debouncedCancel = debounce(() => observer.disconnect(), 500);
+  const debouncedDisconnect = debounce(() => observer.disconnect(), 500);
   observer.observe(document.documentElement);
   callback();
 };

From 5f41c7646b54608e82c7391fb76f6be4640d9b30 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Tue, 3 Feb 2026 11:41:48 -0800
Subject: [PATCH 15/17] format

---
 src/utils/react_props.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/utils/react_props.js b/src/utils/react_props.js
index 6adcde8525..2d9f92178a 100644
--- a/src/utils/react_props.js
+++ b/src/utils/react_props.js
@@ -17,7 +17,7 @@ export const timelineObject = weakMemoize(postElement =>
  * @returns {Promise<object>} The post's buried item property
  */
 export const cellItem = weakMemoize(cellElement =>
-  inject('/main_world/unbury_cell_item.js', [], cellElement)
+  inject('/main_world/unbury_cell_item.js', [], cellElement),
 );
 
 /**

From 4f318b1da5bfef951b3b4301416af205c6007d6e Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Sat, 14 Feb 2026 12:44:28 -0800
Subject: [PATCH 16/17] update new util function

---
 src/utils/react_props.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/utils/react_props.js b/src/utils/react_props.js
index 0208a7642b..4823556413 100644
--- a/src/utils/react_props.js
+++ b/src/utils/react_props.js
@@ -16,9 +16,10 @@ export const timelineObject = postElement => {
  * @param {Element} cellElement An on-screen timeline cell
  * @returns {Promise<object>} The post's buried item property
  */
-export const cellItem = weakMemoize(cellElement =>
-  inject('/main_world/unbury_cell_item.js', [], cellElement),
-);
+export const cellItem = cellElement => {
+  cellElement.cellItemPromise ??= inject('/main_world/unbury_cell_item.js', [], cellElement);
+  return cellElement.cellItemPromise;
+};
 
 /**
  * @param {Element} trailItemElement An on-screen reblog trail item element

From 3fd457a4384f3b73e4b041001e36a15c5af92fe3 Mon Sep 17 00:00:00 2001
From: marcustyphoon <marcustyphoon@gmail.com>
Date: Sat, 14 Feb 2026 12:44:45 -0800
Subject: [PATCH 17/17] fix jsdoc

---
 src/utils/react_props.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/utils/react_props.js b/src/utils/react_props.js
index 4823556413..3971ae6984 100644
--- a/src/utils/react_props.js
+++ b/src/utils/react_props.js
@@ -14,7 +14,7 @@ export const timelineObject = postElement => {
 
 /**
  * @param {Element} cellElement An on-screen timeline cell
- * @returns {Promise<object>} The post's buried item property
+ * @returns {Promise<object>} The element's buried item property
  */
 export const cellItem = cellElement => {
   cellElement.cellItemPromise ??= inject('/main_world/unbury_cell_item.js', [], cellElement);