fix(ui5-popup) page scrolling up if more than one dialog is open (#3431)

Author: kskondov

packages/main/src/Popup.js

@@ -8,7 +8,7 @@ import { isTabPrevious } from "@ui5/webcomponents-base/dist/Keys.js";
 import { getNextZIndex, getFocusedElement, isFocusedElementWithinNode } from "@ui5/webcomponents-base/dist/util/PopupUtils.js";
 import PopupTemplate from "./generated/templates/PopupTemplate.lit.js";
 import PopupBlockLayer from "./generated/templates/PopupBlockLayerTemplate.lit.js";
-import { addOpenedPopup, removeOpenedPopup } from "./popup-utils/OpenedPopupsRegistry.js";
+import { getOpenedPopups, addOpenedPopup, removeOpenedPopup } from "./popup-utils/OpenedPopupsRegistry.js";
 
 // Styles
 import styles from "./generated/themes/Popup.css.js";
@@ -236,7 +236,9 @@ class Popup extends UI5Element {
 	 * @protected
 	 */
 	static blockBodyScrolling() {
-		document.body.style.top = `-${window.pageYOffset}px`;
+		if (window.pageYOffset > 0) {
+			document.body.style.top = `-${window.pageYOffset}px`;
+		}
 		document.body.classList.add("ui5-popup-scroll-blocker");
 	}
 
@@ -395,9 +397,12 @@ class Popup extends UI5Element {
 			return;
 		}
 
+		const openedPopups = getOpenedPopups();
 		if (this.isModal) {
 			this._blockLayerHidden = true;
-			Popup.unblockBodyScrolling();
+			if (openedPopups.length === 1) {
+				Popup.unblockBodyScrolling();
+			}
 		}
 
 		this.hide();

packages/main/test/specs/Dialog.spec.js

@@ -166,3 +166,30 @@ describe("Acc", () => {
 		assert.strictEqual(dialog.shadow$(".ui5-popup-root").getAttribute("aria-label"), accName, "dialog has aria-label.");
 	});
 });
+
+describe("Multiple dialogs page scroll", () => {
+		before(() => {
+			browser.url(`http://localhost:${PORT}/test-resources/pages/Dialog.html`);
+		});
+
+		it("tests multiple dialogs page scrolling", () => {
+			const preventButtonBefore = browser.$("#prevent");
+
+			browser.setWindowSize(400, 400);
+			preventButtonBefore.scrollIntoView();
+
+			const offsetBefore = preventButtonBefore.getLocation('y');
+
+			preventButtonBefore.click();
+
+			browser.keys("Escape");
+			const confirmButton = browser.$("#yes");
+			confirmButton.click();
+
+			browser.setTimeout({ script: 5000 });
+    		const offsetAfter = preventButtonBefore.getLocation('y');
+
+			assert.strictEqual(offsetBefore,  offsetAfter, "No vertical page scrolling when multiple dialogs are closed");
+		});
+
+});