This makes no sense at all. The change you are reverting here is the icon change NOT the text.

When you create a new article then the text has always been Cancel
When you edit an existing article then the text has always been Close

The only thing the pr did was to change the icon that went with the text.

@obuisard this will fix the problem:

return $this->standardButton('cancel', $text, $task)->icon('icon-exit');

This will keep old tookbar-cancell ID but use new icon, from the linked PR.

@brianteeman not quite. It changed the button name. By default the icon is ‘icon-$name’). Hence the icon changed too. But the name also changed the ID of the button which caused test failures in 4.0. I think @Fedik ‘s solution here is correct

yes I see that and I agree with @Fedik

However Allon is saying that the label has changed #40167 (comment)

The label hasn’t changed. @chmst tracked that down in the maintainers group earlier. Allon was wrong about that

it was only 30 minutes ago that he said that :(

The fix from Fedir @Fedik is a good solution but looking at it more closely, brought up to the surface some inconsistencies we have in the toolbars (for instance, we have a 'close' button instead of 'cancel' when creating a new category).

Perhaps I did change the branches too fast and the labels are still the same. Then it is my fault. But the other statement from me is still valid. This should not go into a patch release.

That probably result of George PR #39537,
there for existing item:

ToolbarHelper::cancel('category.cancel', 'JTOOLBAR_CLOSE');
// changed to
$toolbar->cancel('category.cancel');

Probably need

$toolbar->cancel('category.cancel', 'JTOOLBAR_CLOSE');

At

Hmhm, I mean with diferent text :)

Or other way around for diferent text when "new item".

Well, ignore my last comment :)

@obuisard this will fix the problem:

return $this->standardButton('cancel', $text, $task)->icon('icon-exit');

This will keep old tookbar-cancell ID but use new icon, from the linked PR.

So we don't forget @Fedik suggested adding:
->buttonClass('btn btn-primary')
so that icons turn blue.

Reverting the close icon change makes sense given that the replacement of the icon enhances the look and is not fixing a broken/non-loading icon. Additionally, further discussion is needed to be more consistent in the actions, using Close vs Cancel.

Additionally, further discussion is needed to be more consistent in the actions, using Close vs Cancel.

What discussion is needed - this has been the behaviour for a very very long time without issue. The only issue was regarding the icon clashing with the delete icon. Modules dont have the seperate concept of new and edit. Only components do

Thanks Olivier