What functionality is missing? What is unsatisfying with the current situation?

A bookmarking fearute for Articles and most of all Categories, placing them in an easy to reach postion for futher use.  

How does this feature request address the current situation?

  Right now, when worlds become larger (but most of all, and for me this is the bigger part: DEEPER) it often starts filling up with interconnectivity between articles and categories. This is a good thing, but when articles are categoriezed, and subcategorized, and sub-sub-sub-sub categorized it creates a hassel returning to a nestled category to work in the Article-editor page.   It helps that we can write changes to articles main body in the Category view but Articles that has their parent as an article can't. IF you then want to change, for example the sidebar on any article, (as far as i know) you most enter the article-editor page and when finished you are shot back to the highest point of heirarcical structure you have imposed on your categories. Making returing to where you worked a small endeavor (but it adds up).   This is why I want bookmarks I see it implemented as a seperate tab in article-view (so Category, Bookmarked, Type, List, Filter. for example, or any other arrangement), a presentation in which the heirarcy is broken up. Lets present it with a mock-up:
Say you have this structure in the current system:

• E category
• F category
• Af category
• Ef category
• Aef and so on Category
1. Article
2. Article
3. Article
• Ff category
• G category
• H category

It then returns to:

• E category
• F category
• G category
• H category

If you have subdivided it to the point of, lets say 10 layers, you need 10 buttons pressed to navigate there again.
What I imagine is a view that can present categories (and if possible articles) outside of the heirarcy. With the mock earlier it would be like:

• Ee category
• Euclidian Category
• Extreamly-subcategoriezed category
• F category
• Http category
• (Article)

(Proposibly sorted by given weight or alphabeticly) With the mock presenting 5 different categories that has earlier been bookmarked and 1 article.
The Button for bookmarking a category (or maybe even article) should be easy to toggle and I therefore purpose it being beside the other toggles (Draft/Published, Public/Private, WIP/Done). If placed here it can work wonderfuly together with the category search function but more on that in other uses for this feature request.

"Now I here you say: just use the search function" and thats true. But this has as of now 3 shortcomings:

1. LanguageTypos: the system cant differ between letters like Ö and O or ñ and n, a minor flaw
2. This can still force you to write out quite a bit, a minor flaw
3. The system then forces you into viewing only this category so if you plan to work within another category you must go through the same procedure again, a non-minor flaw (not big though)

Having a bookmark feature like proposed below would solve these issues, work in tandem with the current systems and enable a better system to get back to a previus work (more explanation in other uses)

What are other uses for this feature request?

I see an implementation as in the mock having 2 other uses that I think might help in the workflow of worldbuilders and writers alike.
The first use is as a background gathering tool for your current work. Say you are currently fleshing out a Person of Interest (Their name is now Poi), Poi lives in a city (you add it to your bookmarks), he has a connection to 3 different organizations (you add them to your bookmarks), his family, related events you want to weave them into and other things can then be right there when you are writing about them, and if this is implemented at an article level you can have all the information you want, without everything else cluttering your "workspace". How you then use it is by searching in the category searchbar, add it to bookmarks, and then search for the next thing to add.
The Second use is as a "save" tool for getting back into what you were doing when you last were in worldanvil, you can when you bunker down for the night, add your last category used into the bookmarks or point out to your future self where to go next.

With this I also imagine how an integration into the Previewer (alt+Enter for the 2 ppl who have not yet seen god) if it also enableed bookmarking of articles, could really bring the first usecase into the stratosphere. You would then not even need different pages or windows for your different things, you could have all the background you want easily available to you in the preview window whilst you wrote. It can as of now still fullfill this, but as you need to re-search the article you want if you change it i feel like having bookmarks available could still be an addition.