Update position on scroll

packages/components/src/popover/index.js

@@ -135,26 +135,29 @@ const Popover = (
 		? positionToPlacement( position )
 		: placement;
 
-	/**
-	 * Offsets the the position of the popover when the anchor is inside an iframe.
-	 */
-	const frameOffset = useMemo( () => {
-		let ownerDocument = document;
+	const ownerDocument = useMemo( () => {
 		if ( anchorRef?.top ) {
-			ownerDocument = anchorRef?.top.ownerDocument;
+			return anchorRef?.top.ownerDocument;
 		} else if ( anchorRef?.startContainer ) {
-			ownerDocument = anchorRef.startContainer.ownerDocument;
+			return anchorRef.startContainer.ownerDocument;
 		} else if ( anchorRef?.current ) {
-			ownerDocument = anchorRef.current.ownerDocument;
+			return anchorRef.current.ownerDocument;
 		} else if ( anchorRef ) {
 			// This one should be deprecated.
-			ownerDocument = anchorRef.ownerDocument;
+			return anchorRef.ownerDocument;
 		} else if ( anchorRect && anchorRect?.ownerDocument ) {
-			ownerDocument = anchorRect.ownerDocument;
+			return anchorRect.ownerDocument;
 		} else if ( getAnchorRect ) {
-			ownerDocument = getAnchorRect()?.ownerDocument ?? document;
+			return getAnchorRect()?.ownerDocument ?? document;
 		}
 
+		return document;
+	}, [ anchorRef, anchorRect, getAnchorRect ] );
+
+	/**
+	 * Offsets the the position of the popover when the anchor is inside an iframe.
+	 */
+	const frameOffset = useMemo( () => {
 		const { defaultView } = ownerDocument;
 		const { frameElement } = defaultView;
 
@@ -172,7 +175,7 @@ const Popover = (
 				};
 			},
 		};
-	}, [ anchorRef, anchorRect, getAnchorRect ] );
+	}, [ ownerDocument ] );
 
 	const middlewares = [
 		frameOffset,
@@ -310,6 +313,16 @@ const Popover = (
 		};
 	}, [ __unstableObserveElement ] );
 
+	// If we're using getAnchorRect, we need to update the position as we scroll the iframe.
+	useLayoutEffect( () => {
+		if ( ownerDocument === document ) {
+			return;
+		}
+
+		ownerDocument.addEventListener( 'scroll', update );
+		return () => ownerDocument.removeEventListener( 'scroll', update );
+	}, [ ownerDocument ] );
+
 	/** @type {false | string} */
 	const animateClassName =
 		!! animate &&