RichText: remove selection change listener during composition

[ellatrix]

Description

This should be included in WP 5.2. It worked fine in WP 5.1.

Fixes #14434.

This bug can also be reproduced with other keyboards, including an American keyboard.

1. Create a new post and paragraph.
2. Press option+`. You started composing a character.
3. Press any vowel, e.g. a.

Expected: à. Actual: `à.

Cause: the selection change event listener is called after input, which overwrites the DOM if the selection state is different (and it is different, but shouldn't be recorded). The overwrite happens for the format boundaries.

Solution: remove the selection change listener during composition.

Includes a minor clean up, as I was experimenting with different events bound to Editable.

How has this been tested?

See above.

Screenshots

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[youknowriad]

Do you think there's a simpler way togo instead of this selection enabling/disabling? maybe a flag?

[ellatrix]

I see this as the simplest way. There's no need to run a listener if it's not needed?

[ellatrix]

I mean, I think it's "cleanliest" if you remove listeners if you don't need them, add them back if you do need them again. I made the mistake before not to do that, and it had a negative performance impact (#12480), so I make a habit of taking this "cleaner" approach.

[youknowriad]

This fixes the issue for me. I'm wondering, is it possible that the event is not rebound properly in a scenario like this:

• Trigger a composition ^ for instance
• Leave the RichText by clicking outside or something else?

[ellatrix]

@youknowriad Thanks for the review! To answer your question: the browser always triggers a compositionend event, also when a composition is cancelled. When you leave the field, composition ends and the final character is just ^.