For the HackDays in Paris we created a variation of OpenProject in which we used BlockNote for creating work package comments <mention class="mention" data-id="63508" data-type="work_package" data-text="#63508">#63508</mention> . We want to keep those effort for the future. Would be nice to have it cleaned up so far and behind a feature flag, so that we can activate it whenever we need it. Also, that we can continue the development on it whenever our road-map is ready for it.

**Acceptance criteria**

* There is a feature flag \`Block note editor\`

* When it is enabled

* ~~Make BlockNote the editor for the work package comment submit~~

* Decided not to because it would cause extra risk and maintenance on the activity tab

* ~~Make BlockNote the editor for the Wiki~~

* We decided not make it part of the wiki to prevent any possible data inconsistencies between CKEditor and BlockNote

* Make BlockNote the editor for Documents (module)


**How to test**

* Go to _/admin/settings/experimental_

* Enable the _Block note editor_ feature flag

* Go to _admin/settings/document\_categories_ and create a document category called &quot;**Experimental**&quot;

* Go to any project with the documents module enabled (or enable it)

* Go to the documents module and save a document with the category &quot;**Experimental**&quot;

* Edit such document

* See the BlockNote editor


Begin of the insertion**Additional changes**

To be able to properly implement this feature it was necessary to &quot;primerize&quot; the Documents form. This means the UI changes slightly, even when the BlockNote editor is not visible

_Before:_

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/707589/content">

_After:_

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/707590/content">

End of the insertion **Out of scope**

* Replace all other instances of CKEditor 5, e.g. work package description.

* Guaranteeing any CKEditor specific functionality (e.g. @mentions or #expressions)