fix(ui/overlays): overlay growing margin (#2331)

.changeset/avoid-growing-margin.md

@@ -0,0 +1,5 @@
+---
+'@lion/ui': patch
+---
+
+fix: [overlays] avoid growing margin when using `preventsScroll: false`

packages/ui/components/overlays/src/OverlayController.js

@@ -788,6 +788,10 @@ export class OverlayController extends EventTarget {
    * @protected
    */
   _keepBodySize({ phase }) {
+    if (!this.preventsScroll) {
+      return;
+    }
+
     switch (phase) {
       case 'before-show':
         this.__bodyClientWidth = document.body.clientWidth;

packages/ui/components/overlays/test/OverlayController.test.js

@@ -1781,4 +1781,33 @@ describe('OverlayController', () => {
       );
     });
   });
+
+  describe('run _keepBodySize only with scroll prevention', () => {
+    /**
+     * @type {OverlayController}
+     */
+    const overlayControllerNoPrevent = new OverlayController({
+      ...withLocalTestConfig(),
+      preventsScroll: false,
+    });
+
+    const overlayControllerPreventsScroll = new OverlayController({
+      ...withLocalTestConfig(),
+      preventsScroll: true,
+    });
+
+    it('should not run with scroll prevention', async () => {
+      await overlayControllerNoPrevent.show();
+
+      expect(overlayControllerNoPrevent.__bodyMarginRightInline).to.equal(undefined);
+      expect(overlayControllerNoPrevent.__bodyMarginRight).to.equal(undefined);
+    });
+
+    it('should run with scroll prevention', async () => {
+      await overlayControllerPreventsScroll.show();
+
+      expect(overlayControllerPreventsScroll.__bodyMarginRightInline).to.not.equal(undefined);
+      expect(overlayControllerPreventsScroll.__bodyMarginRight).to.not.equal(undefined);
+    });
+  });
 });