Insert button only appears in one instance of Balloon Editor when more than one on the screen

• Type: Impedibug
• Status: Closed
• Priority: Major
• Resolution: Completed
• Affects Version/s: Master
• Fix Version/s: None
• Component/s: CKEditor
• Labels:
  • 7.4-known-issues
  • liferay-ga1-dxp-7413
  • liferay-ga4-ce-743
• Sprint: S04E28 - Bridge over troubl..., S04E29 - Unimagine, S04E30 - Sea Change, S05E01 - Dark Souls
• Git Pull Request: https://github.com/liferay-frontend/liferay-portal/pull/1514

When adding multiple Balloon Editor instances to the Page, the insert button only appears in on of them.

Steps to reproduce:

1. Deploy 'frontend-editor-ckeditor-sample-web' (liferay-portal/tree/master/modules/apps/frontend-editor/frontend-editor-ckeditor-sample-web) with gradle clean deploy
2. Place two instances of CKEditor Sample on a Widget Page
3. Clean text in the first paragraph of the second instance and wait for the insert '+' button to appear
4. Clean text in the first paragraph of the first instance and wait for the insert '+' button to appear

Expected result: The insert button appears in both instances

Actual result: The insert button appears only in the lower instance and it gets impossible to be invoked in the top one.

Verified on: 28/Sept/2021
Environment: localhost
Github: https://github.com/liferay/liferay-portal.git
Branch: master
Bundle: Liferay CE
Last Commit: c7b6198fdeced9882703db93bbbb31a5d6891df4

Note: The Insert button of the second instance is not attached to the area of it (it is visible in the area of the first instance - screen recording attached).