Do not trigger section intersection callbacks from static previews

Prevent triggering the callback when link preview tooltips are
displayed.

REDMINE-20481

Author: tf

entry_types/scrolled/package/spec/frontend/SectionIntersectionObserver-spec.js

@@ -5,6 +5,8 @@ import {
   SectionIntersectionProbe
 } from 'frontend/SectionIntersectionObserver';
 
+import {StaticPreview} from 'frontend/useScrollPositionLifecycle';
+
 import {
   fakeIntersectionObserver,
   simulateScrollingIntoView,
@@ -256,4 +258,26 @@ describe('SectionIntersectionObserver', () => {
     expect(observeSpy).not.toHaveBeenCalled();
     expect(unobserveSpy).not.toHaveBeenCalled();
   });
+
+  it('is no-op inside StaticPreview', () => {
+    const sections = [
+      {id: 1}
+    ];
+    const callback = jest.fn();
+
+    const {getByTestId} = render(
+      <SectionIntersectionObserver sections={sections}
+                                   onChange={callback}>
+        <StaticPreview>
+          <section data-testid="section1">
+            <SectionIntersectionProbe section={sections[0]} />
+          </section>
+        </StaticPreview>
+      </SectionIntersectionObserver>
+    );
+
+    simulateScrollingIntoView(getByTestId('section1'));
+
+    expect(callback).not.toHaveBeenCalled();
+  });
 });

entry_types/scrolled/package/src/frontend/SectionIntersectionObserver.js

@@ -10,6 +10,7 @@ import React, {
 import classNames from 'classnames';
 
 import styles from './SectionIntersectionObserver.module.css';
+import {useIsStaticPreview} from './useScrollPositionLifecycle';
 
 const SectionIntersectionObserverContext = createContext([]);
 
@@ -69,10 +70,16 @@ export function SectionIntersectionObserver({sections, probeClassName, onChange,
 }
 
 export function SectionIntersectionProbe({section}) {
+  const isStaticPreview = useIsStaticPreview();
+
   const observers = useContext(SectionIntersectionObserverContext);
   const probeRefs = useRef([]);
 
   useEffect(() => {
+    if (isStaticPreview) {
+      return;
+    }
+
     const elements = probeRefs.current.slice();
 
     observers.forEach(({observer}, index) => {
@@ -88,7 +95,7 @@ export function SectionIntersectionProbe({section}) {
         }
       });
     };
-  }, [observers]);
+  }, [observers, isStaticPreview]);
 
   return observers.map(({probeClassName}, index) =>
     <div ref={el => probeRefs.current[index] = el}