Add article describing the delayed editor initialisation feature

[sculpt0r]

Added a short article explaining in practice, what is the difference between two options in delayed editor creation.

Closes ckeditor/ckeditor4#4553

[f1ames]

I like the idea of the separate section and the broad description since the concept described here is not that easy to understand 👍 Still, I would try to focus on making the description as simple as possible (which doesn't mean short) to make it easy to understand. I added few suggestions and corrections, but feel free to adjust them further.

I also wonder if we should use term like "editor (parent) element" or maybe "editor container"?

Hmmm, we have both Guides and Features section which is sometimes confusing. Guides are kind of dev guides so the topic of delaying editor (as this is configuration stuff and may require coding) fits there. OTOH it's a feature which can be simply enabled via config so fits in Features section too 🤔
I guess it will be good to have discoverability in mind (how the person not knowing about this feature can find it).

Apart from that I see common cases where it is useful are already mentioned but it will be good to mention cases where it might break something (e.g. editor not initializing) so one may try to disable this feature to solve the issue.

[sculpt0r]

I also wonder if we should use term like "editor (parent) element" or maybe "editor container"?

I thought about that. Probably I should check if I'm 100% consistent here, but:

• I prefer "editor parent element" when we talk about detaching elements. Because not only the closest parent may be detached, but any parent element. And by "editor container" (even according to our API) we are calling the closest parent. 🤔

Hmmm, we have both Guides and Features section which is sometimes confusing. Guides are kind of dev guides so the topic of delaying editor (as this is configuration stuff and may require coding) fits there. OTOH it's a feature which can be simply enabled via config so fits in Features section too 🤔
I guess it will be good to have discoverability in mind (how the person not knowing about this feature can find it).

My way of thinking: Guides are for people who just start with CKEditor or try to achieve some functionality. Features are like "more advanced things" which you can use if you are more proficient with the editor. Also, it was made as a 'feature' during development and it is a kind of non-standard usage.

[sculpt0r]

Hi @f1ames, ready for another review. The changes:

• I correct some ;p;p of the paragraphs
• Added a troubleshooting paragraph - which should exactly show what was the problem with the detached element. And finally, I resign from linking to any GH issue.
• I separate almost every paragraph on two sections: the interval and the callback - which should better visualize differences between those two approaches.
• Added a paragraph how to grab the editor reference when this feature is usage.

[f1ames]

Looks good, I did some corrections here and there - could you take a look?

I still have a feeling that we are missing basic, general overview what this feature does. It is easy to understand for us, but when reading docs it seems we go right away into how to use it and approaches there are. But the introduction is a bit laconic 🤔 WDYT? Maybe we could expand it somehow?

[f1ames]

I would mention here that getting editor ref should be done on instanceReady event. Because when this code is called before editor is created it will fail AFAIR.

[sculpt0r]

Well, you can grab an instance like that, but need to wait for instanceReady anyway to use API. Here, I just want to point out that the old way of creating an editor may return null whereas the object might be returned in the old code.

But, yes - I will mention that :)

[f1ames]

One more thing I forgot to mention during review 🙈 This PR relates to changes in the upcoming CKEditor 4 major so should target major branch.

[sculpt0r]

One more thing I forgot to mention during review 🙈 This PR relates to changes in the upcoming CKEditor 4 major so should target major branch.

The rebasing was kind of painful... So I decided to create another PR but saving commits from this one: #364. Sorry about that.