Constant reboot of TinyMCE

[korenevskiy]

After upgrading to the latest version of joomla 5, this problem appeared, but after updating joomla 6, the software problem also persisted. Even after upgrading to Joomla 6 Alfa, the problem still remained.

I have disabled all Editor-xtd plugins, but the problem still remains. All extensions are also updated. But they do not have the functions to embed something in the editor.

2026-01-21.15-40-45.mp4

Updated: The solution from @brianteeman

I made a hotfix available for you tio use NOW https://github.com/brianteeman/tinymce-firefoxfix/releases

[brianteeman]

Unable to replicate this in any version or branch

[OctavianC]

Can replicate this with Firefox Developer Edition only

[OctavianC]

It dates back to Joomla! 4 so this must be something to do with the browser itself as I haven't noticed it until now.

You can't type into the editor as it's constantly refreshing and losing focus; it seems the browser is initialized in a loop, as it requests editor.css and content.css indefinitely

[Fedik]

@OctavianC can you please try to comment one of these. First only load listener and then only PostRender

joomla-cms/build/media_source/plg_editors_tinymce/js/tinymce.es6.js

Lines 216 to 227 in 0c058e2

	ed.on('load', () => {
	isReady = true;
	if (isRendered) {
	listenIframeReload();
	}
	});
	ed.on('PostRender', () => {
	isRendered = true;
	if (isReady) {
	listenIframeReload();
	}
	});

And check whether it have an effect.

[korenevskiy]

@OctavianC can you please try to comment one of these. First only load listener and then only PostRender

I don't have this file. It's currently running Joomla 6.1 Alfa, the latest. There are files in this folder

tinymce-builder.js
tinymce-builder.min.js
tinymce.js
tinymce.min.js

But the DOM tree change happens in the file
media/vendor/tinymce/themes/silver/theme.js : 2049 and 2145

        `v.dom.insertBefore(element.dom, marker.dom);`
        `dom.parentNode.removeChild(dom);`

these 2 methods are constantly called in sequence.

[OctavianC]

@Fedik commenting either one of them solves the issue. I've also also left them both commented and the editor works fine

[korenevskiy]

@Fedik commenting either one of them solves the issue. I've also also left them both commented and the editor works fine

You're right, I looked at another browser (Yandex(Chromium)).
Everything is working perfectly.
The reboot takes place in Firefox Developer. Of course, it has several extensions installed. But I started the editor in private mode (without extensions), the reboot also happens all the time.

The reboot also happens on other sites in Firefox Developer.
Please check in this browser.

My version Firfox Developer 148 in Vanilla OS(Linux )

[Fedik]

commenting either one of them solves the issue. I've also also left them both commented and the editor works fine

Can you please try to check which exactly of these event cause this behavior? Maybe we can remove one.
The reason there is two because different behavior in browsers. And use of 2 events is a way to render the editor earlier as possible.

Currently the order is:
Chrome:

load
PostRender

Firefox:

PostRender
load

[OctavianC]

Perhaps my message wasn't clear enough:

• Commenting ed.on('load') solves the issue
• Commenting ed.on('PostRender') solves the issue
• Commenting both ed.on('load') and ed.on('PostRender') solves the issue

I've also added a console.log() to see in which order they run:

Results on Firefox Developer shows load and PostRender in a loop:

Results on Firefox shows PostRender and then load:

[Fedik]

Thanks. It is confusing. Maybe bug in Firefox.
And for following code which messages shows up?

    ed.on('load', () => {
        isReady = true;
        if (isRendered) {
          console.log('load');
          listenIframeReload();
        }
      });
      ed.on('PostRender', () => {
        isRendered = true;
        if (isReady) {
          console.log('PostRender');
          listenIframeReload();
        }
      });

[OctavianC]

Just PostRender shows up in a loop

[Fedik]

Thank you for checking.

[brianteeman]

Are we sure that this isnt a tinymce error? Do you get the sane problems when using tinymce examples such as https://www.tiny.cloud/docs/tinymce/latest/full-featured-open-source-demo/

[OctavianC]

Doesn't do that on the TinyMCE demo as the code responsible for this issue is located in

joomla-cms/build/media_source/plg_editors_tinymce/js/tinymce.es6.js

Lines 210 to 224 in eb36442

	// Make sure iframe is fully loaded.
	// This works differently in different browsers, so have to listen both "load" and "PostRender" events.
	ed.on('load', () => {
	isReady = true;
	if (isRendered) {
	listenIframeReload();
	}
	});
	ed.on('PostRender', () => {
	isRendered = true;
	if (isReady) {
	listenIframeReload();
	}
	});
	}