Visual builder requires reload to see content changes

Problem Statement

When we manipulate the page through the visual-builder we have to reload the page to see the added/deleted content.
How common is this issue?

• All questioned users at our company

Who does it impact?

• All contributing users

How severely does it affect them?

• Inconvienience with workaround

How long has this been happening?

• At least since migrating to version 25.05.09-1

If this is a front-end issue, please include the Browser & OS.

• Tested and broken in Edge 135, Chrome 136, and Safari on Mac 15.4.1

There is a few console errors. The biggest one seems to be about contentDocument. Chrome and Edge show an error like this:

ERROR TypeError: Cannot read properties of undefined (reading 'contentDocument')
    at p.no (chunk-FL2Z4EQS.js:39:10969)
    at p.onIframePageLoad (chunk-FL2Z4EQS.js:18:9874)
    at chunk-FL2Z4EQS.js:39:14045
    at tf (chunk-IRNCPZXM.js:8:106146)
    at o (chunk-IRNCPZXM.js:8:106331)
    at HTMLIFrameElement.<anonymous> (chunk-PTQL3SJC.js:2:28587)
    at v.invokeTask (polyfills-E7XIBAE5.js:1:7078)
    at Object.onInvokeTask (chunk-IRNCPZXM.js:8:29812)
    at v.invokeTask (polyfills-E7XIBAE5.js:1:6999)
    at h.runTask (polyfills-E7XIBAE5.js:1:2432)

Safari is slightly different but looks like the same error:

Steps to Reproduce

1. Open a page
2. Check console log

Acceptance Criteria

Items should be added or deleted without needing to reload the entire page.

dotCMS Version

Tested in

• 25.05.09-1
• 25.05.12-1

Proposed Objective

User Experience

Proposed Priority

Priority 2 - Important

External Links... Slack Conversations, Support Tickets, Figma Designs, etc.

No response

Assumptions & Initiation Needs

No response

Quality Assurance Notes & Workarounds

No response

Sub-Tasks & Estimates

No response

Reproduce the issue in the visual builder using the reported browser versions and inspect the console output, especially the contentDocument error. Trace the visual-builder entry point responsible for iframe page-load handling; done means added and deleted items appear without a full-page reload.