Feature/v2/compare tool (#4751)

# Description of Changes

- Addition of the compare tool
- 
---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: James Brunton <[email protected]>

frontend/src/core/components/shared/AppConfigModal.tsx

@@ -1,12 +1,12 @@
 import React, { useMemo, useState, useEffect } from 'react';
 import { Modal, Text, ActionIcon, Tooltip } from '@mantine/core';
-import { useMediaQuery } from '@mantine/hooks';
 import { useNavigate, useLocation } from 'react-router-dom';
 import LocalIcon from '@app/components/shared/LocalIcon';
 import { createConfigNavSections } from '@app/components/shared/config/configNavSections';
 import { NavKey, VALID_NAV_KEYS } from '@app/components/shared/config/types';
 import { useAppConfig } from '@app/contexts/AppConfigContext';
 import '@app/components/shared/AppConfigModal.css';
+import { useIsMobile } from '@app/hooks/useIsMobile';
 import { Z_INDEX_OVER_FULLSCREEN_SURFACE, Z_INDEX_OVER_CONFIG_MODAL } from '@app/styles/zIndex';
 
 interface AppConfigModalProps {
@@ -15,10 +15,10 @@ interface AppConfigModalProps {
 }
 
 const AppConfigModal: React.FC<AppConfigModalProps> = ({ opened, onClose }) => {
+  const [active, setActive] = useState<NavKey>('general');
+  const isMobile = useIsMobile();
   const navigate = useNavigate();
   const location = useLocation();
-  const [active, setActive] = useState<NavKey>('general');
-  const isMobile = useMediaQuery("(max-width: 1024px)");
   const { config } = useAppConfig();
 
   // Extract section from URL path (e.g., /settings/people -> people)

frontend/src/core/components/shared/Tooltip.tsx

@@ -65,6 +65,10 @@ export const Tooltip: React.FC<TooltipProps> = ({
   const clickPendingRef = useRef(false);
   const tooltipIdRef = useRef(`tooltip-${Math.random().toString(36).slice(2)}`);
 
+  // Runtime guard: some browsers may surface non-Node EventTargets for relatedTarget/target
+  const isDomNode = (value: unknown): value is Node =>
+    typeof Node !== 'undefined' && value instanceof Node;
+
   const clearTimers = useCallback(() => {
     if (openTimeoutRef.current) {
       clearTimeout(openTimeoutRef.current);
@@ -103,9 +107,9 @@ export const Tooltip: React.FC<TooltipProps> = ({
     (e: MouseEvent) => {
       const tEl = tooltipRef.current;
       const trg = triggerRef.current;
-      const target = e.target as Node | null;
-      const insideTooltip = tEl && target && tEl.contains(target);
-      const insideTrigger = trg && target && trg.contains(target);
+      const target = e.target as unknown;
+      const insideTooltip = Boolean(tEl && isDomNode(target) && tEl.contains(target));
+      const insideTrigger = Boolean(trg && isDomNode(target) && trg.contains(target));
 
       // If pinned: only close when clicking outside BOTH tooltip & trigger
       if (isPinned) {
@@ -172,7 +176,7 @@ export const Tooltip: React.FC<TooltipProps> = ({
       const related = e.relatedTarget as Node | null;
 
       // Moving into the tooltip → keep open
-      if (related && tooltipRef.current && tooltipRef.current.contains(related)) {
+      if (isDomNode(related) && tooltipRef.current && tooltipRef.current.contains(related)) {
         (children.props as any)?.onPointerLeave?.(e);
         return;
       }
@@ -236,7 +240,7 @@ export const Tooltip: React.FC<TooltipProps> = ({
   const handleBlur = useCallback(
     (e: React.FocusEvent) => {
       const related = e.relatedTarget as Node | null;
-      if (related && tooltipRef.current && tooltipRef.current.contains(related)) {
+      if (isDomNode(related) && tooltipRef.current && tooltipRef.current.contains(related)) {
         (children.props as any)?.onBlur?.(e);
         return;
       }
@@ -258,7 +262,7 @@ export const Tooltip: React.FC<TooltipProps> = ({
   const handleTooltipPointerLeave = useCallback(
     (e: React.PointerEvent) => {
       const related = e.relatedTarget as Node | null;
-      if (related && triggerRef.current && triggerRef.current.contains(related)) return;
+      if (isDomNode(related) && triggerRef.current && triggerRef.current.contains(related)) return;
       if (!isPinned) setOpen(false);
     },
     [isPinned, setOpen]

frontend/src/core/components/shared/TopControls.tsx

@@ -168,7 +168,8 @@ const TopControls = ({
 
   return (
     <div className="absolute left-0 w-full top-0 z-[100] pointer-events-none">
-      <div className="flex justify-center mt-[0.5rem]">
+      <div className="flex justify-center mt-[0.5rem]" style={{ pointerEvents: 'auto' }}>
+
         <SegmentedControl
           data-tour="view-switcher"
           data={createViewOptions(currentView, switchingTo, activeFiles, currentFileIndex, onFileSelect, customViews)}