Fix: prevent pdfjs highlight scrolling from affecting the entire page (#13355)

src-ui/src/app/components/common/preview-popup/preview-popup.component.html

@@ -1,6 +1,7 @@
 <a [href]="link ?? previewUrl" class="{{linkClasses}}" [target]="linkTarget" [title]="linkTitle"
   [ngbPopover]="previewContent" [popoverTitle]="document.title | documentTitle" container="body"
-  autoClose="true" [popoverClass]="popoverClass()" (mouseenter)="mouseEnterPreview()" (mouseleave)="mouseLeavePreview()" #popover="ngbPopover">
+  autoClose="true" [popoverClass]="popoverClass()" [popperOptions]="popperOptions"
+  (mouseenter)="mouseEnterPreview()" (mouseleave)="mouseLeavePreview()" #popover="ngbPopover">
   <ng-content></ng-content>
 </a>
 <ng-template #previewContent>

src-ui/src/app/components/common/preview-popup/preview-popup.component.spec.ts

@@ -67,6 +67,10 @@ describe('PreviewPopupComponent', () => {
     expect(component.useNativePdfViewer).toBeTruthy()
   })
 
+  it('should use fixed positioning for the preview popover', () => {
+    expect(component.popperOptions({}).strategy).toEqual('fixed')
+  })
+
   it('should render object if native PDF viewer enabled', () => {
     settingsService.set(SETTINGS_KEYS.USE_NATIVE_PDF_VIEWER, true)
     component.popover.open()

src-ui/src/app/components/common/preview-popup/preview-popup.component.ts

@@ -8,6 +8,7 @@ import {
   ViewChild,
 } from '@angular/core'
 import { NgbPopover, NgbPopoverModule } from '@ng-bootstrap/ng-bootstrap'
+import { Options } from '@popperjs/core'
 import { NgxBootstrapIconsModule } from 'ngx-bootstrap-icons'
 import { first, Subject, takeUntil } from 'rxjs'
 import { Document } from 'src/app/data/document'
@@ -74,6 +75,11 @@ export class PreviewPopupComponent implements OnDestroy {
 
   readonly popoverClass = signal('shadow popover-preview')
 
+  readonly popperOptions = (options: Partial<Options>): Partial<Options> => ({
+    ...options,
+    strategy: 'fixed',
+  })
+
   get renderAsObject(): boolean {
     return (this.isPdf && this.useNativePdfViewer) || !this.isPdf
   }