Block based widget admin screen causes a NS_ERROR_FAILURE error in Firefox

[walterebert]

On the new widget screen the following error occurs in Firefox 89.0.2 in the console, when loading the page:

Uncaught 
Exception { name: "NS_ERROR_FAILURE", message: "", result: 2147500037, filename: "http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-p…gacy-widget-preview%5Binstance%5D%5Braw%5D%5Bnav_menu%5D=181", lineNumber: 14, columnNumber: 0, data: null, stack: "t.supports[o[r]]<@http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=nav_menu&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=YToxOntzOjg6Im5hdl9tZW51IjtpOjE4MTt9&legacy-widget-preview%5Binstance%5D%5Bhash%5D=2421412fbc986f068f1a768eb85295f7&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bnav_menu%5D=181:14:628\n@http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=nav_menu&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=YToxOntzOjg6Im5hdl9tZW51IjtpOjE4MTt9&legacy-widget-preview%5Binstance%5D%5Bhash%5D=2421412fbc986f068f1a768eb85295f7&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bnav_menu%5D=181:14:1102\n@http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=nav_menu&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=YToxOntzOjg6Im5hdl9tZW51IjtpOjE4MTt9&legacy-widget-preview%5Binstance%5D%5Bhash%5D=2421412fbc986f068f1a768eb85295f7&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bnav_menu%5D=181:14:1779\n" }
widgets.php:14
    t.supports[o[r]]< http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-preview[idBase]=nav_menu&legacy-widget-preview[instance][encoded]=YToxOntzOjg6Im5hdl9tZW51IjtpOjE4MTt9&legacy-widget-preview[instance][hash]=2421412fbc986f068f1a768eb85295f7&legacy-widget-preview[instance][raw][nav_menu]=181:14
    <anonymous> http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-preview[idBase]=nav_menu&legacy-widget-preview[instance][encoded]=YToxOntzOjg6Im5hdl9tZW51IjtpOjE4MTt9&legacy-widget-preview[instance][hash]=2421412fbc986f068f1a768eb85295f7&legacy-widget-preview[instance][raw][nav_menu]=181:14
    <anonymous> http://wpbeta.localhost/wp-admin/widgets.php?legacy-widget-preview[idBase]=nav_menu&legacy-widget-preview[instance][encoded]=YToxOntzOjg6Im5hdl9tZW51IjtpOjE4MTt9&legacy-widget-preview[instance][hash]=2421412fbc986f068f1a768eb85295f7&legacy-widget-preview[instance][raw][nav_menu]=181:14

Tested this in WordPress 5.8-beta4-51244. It seems to be related to the use of a canvas element in an iframe. Also see ​https://bugzilla.mozilla.org/show_bug.cgi?id=941146.

This errors does not occur in other browsers.

[desrosj]

Thanks for this report, @walterebert! And welcome to Trac!

I’m moving this to the milestone for some investigation.

Can you also share more details about your local set up? For example, are you using VVV? Or another local tool?

Also, can you confirm that no plugins are active (including Gutenberg), and that you are using a default theme? And finally, would you be able to test the screen using 5.8 beta 3 to see if you can reproduce in that development release? It could help narrow down the issue.

[Clorith]

And if possible, could you share what widgets you have, and also their settings if possible? I'm not seeing this error in my own local setup, so it may be a specific widget is triggering this. (looking at the error, it seemed like it might be a navigation widget?)

[walterebert]

This is on a new install with the Beta plugin using the Twenty Twenty-One theme. No other plugins are active.

The widgets are in the footer sidebar: search, recent posts, recent comments, archives, categories.

I tested the site with the theme unit test data installed.

My local setup is Linux with Apache and PHP 8.0.7 (using FPM).

[desrosj]

@walterebert could you test with WP 5.8 beta 3 to see if you can reproduce the issue with that release?

[walterebert]

Replying to desrosj:

@walterebert could you test with WP 5.8 beta 3 to see if you can reproduce the issue with that release?

I tried a fresh install and the issue was gone. Upgraded to WP 5.8 beta 4 and everything works fine. Not sure what caused the problem, but I couldn't reproduce the problem so far.

If will try some more things and report back.

[desrosj]

Thanks for retesting! I am going to close this out since you are now unable to reproduce. But if you do encounter it again, feel free to reopen with more details!

[desrosj]

I actually just encountered this testing #53512. It seems to happen when an Image widget is added to a sidebar before updating to a WordPress 5.8 development build.

I'm only able to reproduce in Firefox.

I'm going to reopen to investigate further, But it doesn't appear that anything is actually broken at first glance. The widget previews all load, I'm able to add new widgets, and I'm able to change all of the widgets found on the page (including the image widget that appears to cause the issue.

Uncaught 
Exception { name: "NS_ERROR_FAILURE", message: "", result: 2147500037, filename: "http://localhost:10018/wp-admin/widgets.php?legacy-widget-pr…jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=", lineNumber: 17, columnNumber: 0, data: null, stack: "t.supports[o[r]]<@http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=media_image&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=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%3D&legacy-widget-preview%5Binstance%5D%5Bhash%5D=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bsize%5D=medium&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bwidth%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bheight%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bcaption%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Balt%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_type%5D=custom&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_url%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_rel%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_target_blank%5D=false&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_title%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Battachment_id%5D=52&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Burl%5D=http%3A%2F%2Flocalhost%3A10018%2Fwp-content%2Fuploads%2F2021%2F06%2Fdenys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=:17:628\n@http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=media_image&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=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%3D&legacy-widget-preview%5Binstance%5D%5Bhash%5D=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bsize%5D=medium&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bwidth%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bheight%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bcaption%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Balt%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_type%5D=custom&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_url%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_rel%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_target_blank%5D=false&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_title%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Battachment_id%5D=52&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Burl%5D=http%3A%2F%2Flocalhost%3A10018%2Fwp-content%2Fuploads%2F2021%2F06%2Fdenys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=:17:1102\n@http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=media_image&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=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%3D&legacy-widget-preview%5Binstance%5D%5Bhash%5D=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bsize%5D=medium&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bwidth%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bheight%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bcaption%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Balt%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_type%5D=custom&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_url%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_rel%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_target_blank%5D=false&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_title%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Battachment_id%5D=52&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Burl%5D=http%3A%2F%2Flocalhost%3A10018%2Fwp-content%2Fuploads%2F2021%2F06%2Fdenys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=:17:1779\n" }
​
columnNumber: 0
​
data: null
​
filename: "http://localhost:10018/wp-admin/widgets.php?legacy-widget-pr…jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D="
​
lineNumber: 17
​
message: ""
​
name: "NS_ERROR_FAILURE"
​
result: 2147500037
​
stack: "t.supports[o[r]]<@http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=media_image&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=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%3D&legacy-widget-preview%5Binstance%5D%5Bhash%5D=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bsize%5D=medium&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bwidth%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bheight%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bcaption%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Balt%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_type%5D=custom&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_url%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_rel%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_target_blank%5D=false&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_title%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Battachment_id%5D=52&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Burl%5D=http%3A%2F%2Flocalhost%3A10018%2Fwp-content%2Fuploads%2F2021%2F06%2Fdenys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=:17:628\n@http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=media_image&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=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%3D&legacy-widget-preview%5Binstance%5D%5Bhash%5D=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bsize%5D=medium&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bwidth%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bheight%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bcaption%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Balt%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_type%5D=custom&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_url%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_rel%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_target_blank%5D=false&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_title%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Battachment_id%5D=52&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Burl%5D=http%3A%2F%2Flocalhost%3A10018%2Fwp-content%2Fuploads%2F2021%2F06%2Fdenys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=:17:1102\n@http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview%5BidBase%5D=media_image&legacy-widget-preview%5Binstance%5D%5Bencoded%5D=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%3D&legacy-widget-preview%5Binstance%5D%5Bhash%5D=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bsize%5D=medium&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bwidth%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bheight%5D=2560&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bcaption%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Balt%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_type%5D=custom&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_url%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_classes%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_rel%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Blink_target_blank%5D=false&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Bimage_title%5D=&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Battachment_id%5D=52&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Burl%5D=http%3A%2F%2Flocalhost%3A10018%2Fwp-content%2Fuploads%2F2021%2F06%2Fdenys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview%5Binstance%5D%5Braw%5D%5Btitle%5D=:17:1779\n"
​
<prototype>: ExceptionPrototype { toString: toString(), name: Getter, message: Getter, … }
widgets.php:17
    t.supports[o[r]]< http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview[idBase]=media_image&legacy-widget-preview[instance][encoded]=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&legacy-widget-preview[instance][hash]=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview[instance][raw][size]=medium&legacy-widget-preview[instance][raw][width]=2560&legacy-widget-preview[instance][raw][height]=2560&legacy-widget-preview[instance][raw][caption]=&legacy-widget-preview[instance][raw][alt]=&legacy-widget-preview[instance][raw][link_type]=custom&legacy-widget-preview[instance][raw][link_url]=&legacy-widget-preview[instance][raw][image_classes]=&legacy-widget-preview[instance][raw][link_classes]=&legacy-widget-preview[instance][raw][link_rel]=&legacy-widget-preview[instance][raw][link_target_blank]=false&legacy-widget-preview[instance][raw][image_title]=&legacy-widget-preview[instance][raw][attachment_id]=52&legacy-widget-preview[instance][raw][url]=http://localhost:10018/wp-content/uploads/2021/06/denys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview[instance][raw][title]=:17
    <anonymous> http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview[idBase]=media_image&legacy-widget-preview[instance][encoded]=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&legacy-widget-preview[instance][hash]=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview[instance][raw][size]=medium&legacy-widget-preview[instance][raw][width]=2560&legacy-widget-preview[instance][raw][height]=2560&legacy-widget-preview[instance][raw][caption]=&legacy-widget-preview[instance][raw][alt]=&legacy-widget-preview[instance][raw][link_type]=custom&legacy-widget-preview[instance][raw][link_url]=&legacy-widget-preview[instance][raw][image_classes]=&legacy-widget-preview[instance][raw][link_classes]=&legacy-widget-preview[instance][raw][link_rel]=&legacy-widget-preview[instance][raw][link_target_blank]=false&legacy-widget-preview[instance][raw][image_title]=&legacy-widget-preview[instance][raw][attachment_id]=52&legacy-widget-preview[instance][raw][url]=http://localhost:10018/wp-content/uploads/2021/06/denys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview[instance][raw][title]=:17
    <anonymous> http://localhost:10018/wp-admin/widgets.php?legacy-widget-preview[idBase]=media_image&legacy-widget-preview[instance][encoded]=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&legacy-widget-preview[instance][hash]=0aba49757eacc13425bb3a83539c03bd&legacy-widget-preview[instance][raw][size]=medium&legacy-widget-preview[instance][raw][width]=2560&legacy-widget-preview[instance][raw][height]=2560&legacy-widget-preview[instance][raw][caption]=&legacy-widget-preview[instance][raw][alt]=&legacy-widget-preview[instance][raw][link_type]=custom&legacy-widget-preview[instance][raw][link_url]=&legacy-widget-preview[instance][raw][image_classes]=&legacy-widget-preview[instance][raw][link_classes]=&legacy-widget-preview[instance][raw][link_rel]=&legacy-widget-preview[instance][raw][link_target_blank]=false&legacy-widget-preview[instance][raw][image_title]=&legacy-widget-preview[instance][raw][attachment_id]=52&legacy-widget-preview[instance][raw][url]=http://localhost:10018/wp-content/uploads/2021/06/denys-nevozhai-1183974-unsplash-1-300x300.jpg&legacy-widget-preview[instance][raw][title]=:17

[Clorith]

Looks like this might be a FireFox bug, relating to the use of iframes, which sounds about right for images in a legacy widget, since they would trigger an iframe for previewing.

​https://bugzilla.mozilla.org/show_bug.cgi?id=941146

I wonder if things do not appear broken right now due to the editor and the preview of legacy widgets being displayed at the same time, and if you click into them, the preview disappears, for images the editor includes a preview of the image as well, so you should, in theory, see two identical images coming in one after the other if you're just looking at the widget list in wp-admin.

[JeffPaul]

With no patch/PR nor clear owner on this ticket and with 5.8 RC 1 tomorrow, I'm going to punt this to Future Release though hopefully this can get addressed in Firefox or upstream in Gutenberg and get into 5.8.1 or 5.9.

[prionkor]

After upgrading to wordpress 5.8 my widget page is broken with this error (all white), sidebar and WordPress admin bar still loads.

[prionkor]

In chrome I don't see any errors in console but the widget screen is still white.

[airofoil]

Hey - had these errors (30+) in both Firefox and Chrome, using the Gutenberg widgets.php

I have a feeling it's crashing other JS on the page and making inner-widget buttons unusable

I actually have custom widgets in there that I initialised (functions.php), that are smoothly integrated and working with the classic widget area, but s'pose it is likely they're incompatible with the block editor

My solution was installing the Classic Widgets plugin which fixed it instantly & without a single console error

[jqz]

Same error with Customizer in WP 5.5.7 with Firefox. Triggers (blank) grey screen of death in Customizer parent frame. AFAIAA, Gutenberg Widgets were not introduced until WP 5.8...

Error is at t.supports[o[r]] in some apparently inline JavaScript. WTH is inlining minified JS?!?

[jqz]

The error is in the wpemojiSettings script, which should have been implemented properly long ago (instead of being left as the initial hack it still appears to be).

[jqz]

There are multiple issues here.

The Customizer communicates with its child iframe, but upon detecting an error removes all content from the page, including the child iframe itself. There is no reason AFAICS for it to do this, and it makes it hard to debug. The Customizer also removes controls from the parent frame if they are not defined in the child frame (e.g. try adding a setting/control conditional on is_admin()). Is there any reason for all this?

The actual exception seems to be in emojiSetsRenderIdentically(), which uses Canvas. This function needs to be able to handle exceptions.

However, if the Customizer parent didn't bomb out upon this, there wouldn't be too much of a problem. Because it does, the Customizer can't be used when this error is occuring.

Two fixes are needed:

• Handle exception in emojiSetsRenderIdentically(), somehow;
• Stop Customizer removing content based on messages from child iframe (or if content is removed upon error, make damn sure it's correct to do so).

[bozzmedia]

Still running into this issue in WP 6.0, Firefox, Win10. The error locks me out of saving widgets in the new widget editor.

Interestingly the NS_ERROR_FAILURE and Invalid JSON response error pops up when I try to introduce and then save an Image block or Custom HTML block in the Widget editor. Don't get the same error with social icons block, nav menu block, or paragraph block.