Check for parent overflow only once.

packages/block-editor/src/utils/dom.js

@@ -140,23 +140,37 @@ export function getVisibleElementBounds( element ) {
 		return new window.DOMRectReadOnly();
 	}
 
-	let bounds = element.getBoundingClientRect();
+	const parentRect = element.getBoundingClientRect();
+	let bounds = parentRect;
 
 	const stack = [ element ];
+	const xValues = [];
+	const yValues = [];
 	let currentElement;
 
 	while ( ( currentElement = stack.pop() ) ) {
 		for ( const child of currentElement.children ) {
 			if ( isElementVisible( child ) ) {
 				const childBounds = child.getBoundingClientRect();
-				// If the child is larger than the parent, adjust the x and y values to account for any scrolling.
-				if ( childBounds.width > bounds.width ) {
-					childBounds.x = bounds.x;
+				yValues.push( childBounds.y );
+				xValues.push( childBounds.x );
+				/*
+				 * If the child is larger than the parent, adjust the x and y values to the greatest known
+				 * to account for any scrolling.
+				 */
+				if ( childBounds.width > parentRect.width ) {
+					childBounds.x = Math.max(
+						parentRect.x,
+						xValues.sort().at( -1 ) || 0
+					);
 				}
-				if ( childBounds.height > bounds.height ) {
-					childBounds.y = bounds.y;
-					childBounds.height = bounds.height;
+				if ( childBounds.height > parentRect.height ) {
+					childBounds.y = Math.max(
+						parentRect.y,
+						yValues.sort().at( -1 ) || 0
+					);
 				}
+
 				bounds = rectUnion( bounds, childBounds );
 				stack.push( child );
 			}
@@ -173,12 +187,12 @@ export function getVisibleElementBounds( element ) {
 	 */
 	const left = Math.max( bounds.left, 0 );
 	const right = Math.min( bounds.right, viewport.innerWidth );
+
 	bounds = new window.DOMRectReadOnly(
 		left,
 		bounds.top,
 		right - left,
 		bounds.height
 	);
-
 	return bounds;
 }