CTRL+Z/Y (undo/redo) blocked in source mode

[Piotrek Koszuliński]

Unfortunately fix for #11126 touched also source mode, so undoing and redoing is completely impossible.

We need to find a way to block those keystrokes only in wysiwyg mode. I'm not sure how can we achieve this in a clean way, because blockedKeystroke is mode-blind and undo/redo commands are not even executed at the bottom/top of the stack, because they are disabled then.

Our API does not leave us much choice (if any), so new option may need to be proposed.

[Olek Nowodziński]

I don't think it's critical. It's been two months since the release of 4.3.2 and no one (?) submitted a bug. Either very few users care about undo support in Source Mode (Source Mode in general?) or this behavior is considered a feature of editor, implemented by purpose.

[Piotrek Koszuliński]

I would rather say that it's one of these bugs which you can workaround very easily, so you quickly forget and don't want to waste time on reporting. But it's still a regression and I noticed that something is wrong few weeks ago. I just didn't think that it's a CKEditor's issue, because browsers have problems with undo/redo too.

[Frederico Caldeira Knabben]

This is certainly bad. Undo is the kind of feature that a user MUST trust. It's like "ok, I'll try this out and if it'll not work I'm fine because I can undo". It's one of the most basic UX requirements, especially for an editor.

[Piotrek Koszuliński]

Solution:

1. Revert patch for #11126.
2. In undo plugin, add an editor#key listener which will prevent default action when in wysiwyg mode.

[Piotrek Koszuliński]

Pushed ​branch:t/11677 on dev and tests. The solution could not be simpler, because cancelling editor#key prevents also from executing commands. This change in the key event would make it more powerful: ​http://dev.ckeditor.com/ticket/4264#comment:5.

Additionally, I found out that the this is not any more needed: ​https://github.com/ckeditor/ckeditor-dev/blob/32de5b622320da89c01f9ecd989923011beaa2ac/core/keystrokehandler.js#L90 I'll create a ticket because I saw that hack in many places.

[Piotrek Koszuliński]

Reported: #11739.

[Piotrek Koszuliński]

Fixed on master with ​git:954f689 on dev and 40abd29 on tests.